Remove zon comment (#1265)

Resolve type of simple labeled block

build.zig.zon

@@ -16,7 +16,6 @@
             .hash = "122041f6531ee2cd10e7d5f81817c50b45037affc95d748cbcd71a766866fb6030d4",
         },
         .binned_allocator = .{
-            // upstream: https://gist.github.com/silversquirl/c1e4840048fdf48e669b6eac76d80634
             .url = "https://gist.github.com/FalsePattern/48fded613c115e16e91c46db8642c7e4/archive/75e3d5e6a0e0cf23dbf7abfe16831e23c38721bc.tar.gz",
             .hash = "1220ba896ddd4258eed9274b36284d4cc4600ee69c4c0978cbe237ec09a524a2e252",
         },

src/ZigCompileServer.zig

@@ -32,32 +32,27 @@ pub fn receiveMessage(client: *Client) !InMessage.Header {
     const Header = InMessage.Header;
     const fifo = client.pooler.fifo(.in);
 
-    while (try client.pooler.poll()) {
+    var first_run = true;
-        const buf = fifo.readableSlice(0);
+    var header: ?Header = null;
-        assert(fifo.readableLength() == buf.len);
+    while (first_run or try client.pooler.poll()) {
-        if (buf.len >= @sizeOf(Header)) {
+        first_run = false;
-            // workaround for https://github.com/ziglang/zig/issues/14904
+
+        if (header == null) {
+            if (fifo.readableLength() < @sizeOf(Header)) continue;
+            const buf = fifo.readableSlice(0);
             const bytes_len = bswap_and_workaround_u32(buf[4..][0..4]);
             const tag = bswap_and_workaround_tag(buf[0..][0..4]);
-
+            header = Header{
-            if (buf.len - @sizeOf(Header) >= bytes_len) {
+                .tag = tag,
-                fifo.discard(@sizeOf(Header));
+                .bytes_len = bytes_len,
-                return .{
+            };
-                    .tag = tag,
+            fifo.discard(@sizeOf(Header));
-                    .bytes_len = bytes_len,
-                };
-            } else {
-                const needed = bytes_len - (buf.len - @sizeOf(Header));
-                const write_buffer = try fifo.writableWithSize(needed);
-                const amt = try client.in.readAll(write_buffer);
-                fifo.update(amt);
-                continue;
-            }
         }
 
-        const write_buffer = try fifo.writableWithSize(256);
+        if (header) |h| {
-        const amt = try client.in.read(write_buffer);
+            if (fifo.readableLength() < h.bytes_len) continue;
-        fifo.update(amt);
+            return h;
+        }
     }
     return error.Timeout;
 }

src/analyser/InternPool.zig

@@ -338,7 +338,7 @@ pub const Key = union(enum) {
                 .anyerror => .ErrorSet,
                 .noreturn => .NoReturn,
                 .anyframe_type => .AnyFrame,
-                .empty_struct_literal => .Struct,
+                .empty_struct_type => .Struct,
                 .null_type => .Null,
                 .undefined_type => .Undefined,
                 .enum_literal_type => .EnumLiteral,
@@ -634,7 +634,7 @@ pub const Key = union(enum) {
                 .enum_literal_type,
                 => Index.none,
 
-                .empty_struct_literal => Index.empty_aggregate,
+                .empty_struct_type => Index.empty_aggregate,
                 .void => Index.void_value,
                 .noreturn => Index.unreachable_value,
                 .null_type => Index.null_value,
@@ -659,8 +659,8 @@ pub const Key = union(enum) {
             .int_type => |int_info| {
                 if (int_info.bits == 0) {
                     switch (int_info.signedness) {
-                        .unsigned => return Index.zero,
+                        .unsigned => return Index.zero_comptime_int,
-                        .signed => return Index.zero, // do we need a signed zero?
+                        .signed => return Index.zero_comptime_int, // do we need a signed zero?
                     }
                 }
                 return Index.none;
@@ -835,7 +835,7 @@ pub const Key = union(enum) {
 
                 .null_type => try writer.writeAll("@TypeOf(null)"),
                 .undefined_type => try writer.writeAll("@TypeOf(undefined)"),
-                .empty_struct_literal => try writer.writeAll("@TypeOf(.{})"),
+                .empty_struct_type => try writer.writeAll("@TypeOf(.{})"),
                 .enum_literal_type => try writer.writeAll("@TypeOf(.enum_literal)"),
 
                 .atomic_order => try writer.writeAll("std.builtin.AtomicOrder"),
@@ -1104,7 +1104,7 @@ pub const Index = enum(u32) {
     comptime_float_type,
     noreturn_type,
     anyframe_type,
-    empty_struct_literal,
+    empty_struct_type,
     null_type,
     undefined_type,
     enum_literal_type,
@@ -1114,19 +1114,22 @@ pub const Index = enum(u32) {
     address_space_type,
     float_mode_type,
     reduce_op_type,
-    modifier_type,
+    call_modifier_type,
     prefetch_options_type,
     export_options_type,
     extern_options_type,
     type_info_type,
     manyptr_u8_type,
     manyptr_const_u8_type,
+    manyptr_const_u8_sentinel_0_type,
     fn_noreturn_no_args_type,
     fn_void_no_args_type,
     fn_naked_noreturn_no_args_type,
     fn_ccc_void_no_args_type,
     single_const_pointer_to_comptime_int_type,
-    const_slice_u8_type,
+    slice_const_u8_type,
+    slice_const_u8_sentinel_0_type,
+    optional_noreturn_type,
     anyerror_void_error_union_type,
     generic_poison_type,
     unknown_type,
@@ -1134,9 +1137,17 @@ pub const Index = enum(u32) {
     /// `undefined` (untyped)
     undefined_value,
     /// `0` (comptime_int)
-    zero,
+    zero_comptime_int,
+    /// `0` (u8)
+    zero_u8,
+    /// `0` (usize)
+    zero_usize,
     /// `1` (comptime_int)
-    one,
+    one_comptime_int,
+    /// `1` (u8)
+    one_u8,
+    /// `1` (usize)
+    one_usize,
     /// `{}`
     void_value,
     /// `unreachable` (noreturn type)
@@ -1149,10 +1160,6 @@ pub const Index = enum(u32) {
     bool_false,
     /// `.{}` (untyped)
     empty_aggregate,
-    /// `0` (usize)
-    zero_usize,
-    /// `1` (usize)
-    one_usize,
     the_only_possible_value,
     generic_poison,
     // unknown value of unknown type
@@ -1345,7 +1352,7 @@ pub const SimpleType = enum(u32) {
     comptime_float,
     noreturn,
     anyframe_type,
-    empty_struct_literal,
+    empty_struct_type,
     null_type,
     undefined_type,
     enum_literal_type,
@@ -1424,7 +1431,7 @@ pub fn init(gpa: Allocator) Allocator.Error!InternPool {
         .{ .index = .comptime_float_type, .key = .{ .simple_type = .comptime_float } },
         .{ .index = .noreturn_type, .key = .{ .simple_type = .noreturn } },
         .{ .index = .anyframe_type, .key = .{ .simple_type = .anyframe_type } },
-        .{ .index = .empty_struct_literal, .key = .{ .simple_type = .empty_struct_literal } },
+        .{ .index = .empty_struct_type, .key = .{ .simple_type = .empty_struct_type } },
         .{ .index = .null_type, .key = .{ .simple_type = .null_type } },
         .{ .index = .undefined_type, .key = .{ .simple_type = .undefined_type } },
         .{ .index = .enum_literal_type, .key = .{ .simple_type = .enum_literal_type } },
@@ -1435,41 +1442,45 @@ pub fn init(gpa: Allocator) Allocator.Error!InternPool {
         .{ .index = .address_space_type, .key = .{ .simple_type = .address_space } },
         .{ .index = .float_mode_type, .key = .{ .simple_type = .float_mode } },
         .{ .index = .reduce_op_type, .key = .{ .simple_type = .reduce_op } },
-        .{ .index = .modifier_type, .key = .{ .simple_type = .modifier } },
+        .{ .index = .call_modifier_type, .key = .{ .simple_type = .modifier } },
         .{ .index = .prefetch_options_type, .key = .{ .simple_type = .prefetch_options } },
         .{ .index = .export_options_type, .key = .{ .simple_type = .export_options } },
         .{ .index = .extern_options_type, .key = .{ .simple_type = .extern_options } },
         .{ .index = .type_info_type, .key = .{ .simple_type = .type_info } },
         .{ .index = .manyptr_u8_type, .key = .{ .pointer_type = .{ .elem_type = .u8_type, .size = .Many } } },
         .{ .index = .manyptr_const_u8_type, .key = .{ .pointer_type = .{ .elem_type = .u8_type, .size = .Many, .is_const = true } } },
+        .{ .index = .manyptr_const_u8_sentinel_0_type, .key = .{ .pointer_type = .{ .elem_type = .u8_type, .sentinel = .zero_u8, .size = .Many, .is_const = true } } },
         .{ .index = .fn_noreturn_no_args_type, .key = .{ .function_type = .{ .args = &.{}, .return_type = .noreturn_type } } },
         .{ .index = .fn_void_no_args_type, .key = .{ .function_type = .{ .args = &.{}, .return_type = .void_type } } },
         .{ .index = .fn_naked_noreturn_no_args_type, .key = .{ .function_type = .{ .args = &.{}, .return_type = .void_type, .calling_convention = .Naked } } },
         .{ .index = .fn_ccc_void_no_args_type, .key = .{ .function_type = .{ .args = &.{}, .return_type = .void_type, .calling_convention = .C } } },
         .{ .index = .single_const_pointer_to_comptime_int_type, .key = .{ .pointer_type = .{ .elem_type = .comptime_int_type, .size = .One, .is_const = true } } },
-        .{ .index = .const_slice_u8_type, .key = .{ .pointer_type = .{ .elem_type = .u8_type, .size = .Slice, .is_const = true } } },
+        .{ .index = .slice_const_u8_type, .key = .{ .pointer_type = .{ .elem_type = .u8_type, .size = .Slice, .is_const = true } } },
+        .{ .index = .slice_const_u8_sentinel_0_type, .key = .{ .pointer_type = .{ .elem_type = .u8_type, .sentinel = .zero_u8, .size = .Slice, .is_const = true } } },
+        .{ .index = .optional_noreturn_type, .key = .{ .optional_type = .{ .payload_type = .noreturn_type } } },
         .{ .index = .anyerror_void_error_union_type, .key = .{ .error_union_type = .{ .error_set_type = .anyerror_type, .payload_type = .void_type } } },
         .{ .index = .generic_poison_type, .key = .{ .simple_type = .generic_poison } },
         .{ .index = .unknown_type, .key = .{ .simple_type = .unknown } },
 
         .{ .index = .undefined_value, .key = .{ .simple_value = .undefined_value } },
-        .{ .index = .zero, .key = .{ .int_u64_value = .{ .ty = .comptime_int_type, .int = 0 } } },
+        .{ .index = .zero_comptime_int, .key = .{ .int_u64_value = .{ .ty = .comptime_int_type, .int = 0 } } },
-        .{ .index = .one, .key = .{ .int_u64_value = .{ .ty = .comptime_int_type, .int = 1 } } },
+        .{ .index = .zero_u8, .key = .{ .int_u64_value = .{ .ty = .u8_type, .int = 0 } } },
+        .{ .index = .zero_usize, .key = .{ .int_u64_value = .{ .ty = .usize_type, .int = 0 } } },
+        .{ .index = .one_comptime_int, .key = .{ .int_u64_value = .{ .ty = .comptime_int_type, .int = 1 } } },
+        .{ .index = .one_u8, .key = .{ .int_u64_value = .{ .ty = .u8_type, .int = 1 } } },
+        .{ .index = .one_usize, .key = .{ .int_u64_value = .{ .ty = .usize_type, .int = 1 } } },
         .{ .index = .void_value, .key = .{ .simple_value = .void_value } },
         .{ .index = .unreachable_value, .key = .{ .simple_value = .unreachable_value } },
         .{ .index = .null_value, .key = .{ .simple_value = .null_value } },
         .{ .index = .bool_true, .key = .{ .simple_value = .bool_true } },
         .{ .index = .bool_false, .key = .{ .simple_value = .bool_false } },
-
+        .{ .index = .empty_aggregate, .key = .{ .aggregate = .{ .ty = .empty_struct_type, .values = &.{} } } },
-        .{ .index = .empty_aggregate, .key = .{ .aggregate = .{ .ty = .empty_struct_literal, .values = &.{} } } },
-        .{ .index = .zero_usize, .key = .{ .int_u64_value = .{ .ty = .usize_type, .int = 0 } } },
-        .{ .index = .one_usize, .key = .{ .int_u64_value = .{ .ty = .usize_type, .int = 1 } } },
         .{ .index = .the_only_possible_value, .key = .{ .simple_value = .the_only_possible_value } },
         .{ .index = .generic_poison, .key = .{ .simple_value = .generic_poison } },
         .{ .index = .unknown_unknown, .key = .{ .unknown_value = .{ .ty = .unknown_type } } },
     };
 
-    const extra_count = 4 * @sizeOf(Pointer) + @sizeOf(ErrorUnion) + 4 * @sizeOf(Function) + 4 * @sizeOf(InternPool.U64Value);
+    const extra_count = 6 * @sizeOf(Pointer) + @sizeOf(ErrorUnion) + 4 * @sizeOf(Function) + 6 * @sizeOf(InternPool.U64Value);
 
     try ip.map.ensureTotalCapacity(gpa, items.len);
     try ip.items.ensureTotalCapacity(gpa, items.len);
@@ -3107,7 +3118,7 @@ test "pointer type" {
     const @"[*:0]u32" = try ip.get(gpa, .{ .pointer_type = .{
         .elem_type = .u32_type,
         .size = .Many,
-        .sentinel = .zero,
+        .sentinel = .zero_comptime_int,
     } });
     const @"[]u32" = try ip.get(gpa, .{ .pointer_type = .{
         .elem_type = .u32_type,
@@ -3116,7 +3127,7 @@ test "pointer type" {
     const @"[:0]u32" = try ip.get(gpa, .{ .pointer_type = .{
         .elem_type = .u32_type,
         .size = .Slice,
-        .sentinel = .zero,
+        .sentinel = .zero_comptime_int,
     } });
     const @"[*c]u32" = try ip.get(gpa, .{ .pointer_type = .{
         .elem_type = .u32_type,
@@ -3233,7 +3244,7 @@ test "array type" {
     const u32_0_0_array_type = try ip.get(gpa, .{ .array_type = .{
         .len = 3,
         .child = .u32_type,
-        .sentinel = .zero,
+        .sentinel = .zero_comptime_int,
     } });
 
     try expect(i32_3_array_type != u32_0_0_array_type);

src/analysis.zig

@@ -989,16 +989,22 @@ fn resolveTypeOfNodeUncached(analyser: *Analyser, node_handle: NodeWithHandle) e
 
             const cast_map = std.ComptimeStringMap(void, .{
                 .{"@as"},
+                .{"@atomicLoad"},
+                .{"@atomicRmw"},
+                .{"@atomicStore"},
                 .{"@bitCast"},
-                .{"@fieldParentPtr"},
+                .{"@mulAdd"},
+                .{"@errSetCast"},
+                .{"@fieldParentPtr"}, // the return type is actually a pointer
                 .{"@floatCast"},
-                .{"@floatToInt"},
+                .{"@intFromFloat"},
                 .{"@intCast"},
-                .{"@intToEnum"},
+                .{"@enumFromInt"},
-                .{"@intToFloat"},
+                .{"@floatFromInt"},
-                .{"@intToPtr"},
+                .{"@ptrFromInt"},
-                .{"@truncate"},
                 .{"@ptrCast"},
+                .{"@truncate"},
+                .{"@unionInit"},
             });
             if (cast_map.has(call_name)) {
                 if (params.len < 1) return null;
@@ -1134,6 +1140,33 @@ fn resolveTypeOfNodeUncached(analyser: *Analyser, node_handle: NodeWithHandle) e
                 .handle = handle,
             };
         },
+        .block,
+        .block_semicolon,
+        .block_two,
+        .block_two_semicolon,
+        => {
+            const first_token = tree.firstToken(node);
+            if (token_tags[first_token] != .identifier) return null;
+
+            const block_label = tree.tokenSlice(first_token);
+
+            var buffer: [2]Ast.Node.Index = undefined;
+            const statements = ast.blockStatements(tree, node, &buffer).?;
+
+            for (statements) |child_idx| {
+                // TODO: Recursively find matching `break :label` (e.g. inside `if`)
+                if (node_tags[child_idx] == .@"break") {
+                    if (datas[child_idx].lhs == 0) continue;
+                    if (datas[child_idx].rhs == 0) continue;
+
+                    const break_label = tree.tokenSlice(datas[child_idx].lhs);
+                    if (!std.mem.eql(u8, block_label, break_label)) continue;
+
+                    const operand = .{ .node = datas[child_idx].rhs, .handle = handle };
+                    return try analyser.resolveTypeOfNodeInternal(operand);
+                }
+            }
+        },
         else => {},
     }
     return null;

src/features/inlay_hints.zig

@@ -84,24 +84,31 @@ fn writeCallHint(builder: *Builder, call: Ast.full.Call, decl_handle: Analyser.D
     var buffer: [1]Ast.Node.Index = undefined;
     const fn_proto = decl_tree.fullFnProto(&buffer, fn_node) orelse return;
 
-    var i: usize = 0;
+    var params = try std.ArrayListUnmanaged(Ast.full.FnProto.Param).initCapacity(builder.arena, fn_proto.ast.params.len);
-    var it = fn_proto.iterate(&decl_tree);
+    defer params.deinit(builder.arena);
 
-    if (try builder.analyser.hasSelfParam(decl_handle.handle, fn_proto)) {
+    var it = fn_proto.iterate(&decl_tree);
-        _ = ast.nextFnParam(&it);
+    while (ast.nextFnParam(&it)) |param| {
+        try params.append(builder.arena, param);
     }
 
-    while (ast.nextFnParam(&it)) |param| : (i += 1) {
+    const has_self_param = tree.tokens.items(.tag)[call.ast.lparen - 2] == .period and
-        if (i >= call.ast.params.len) break;
+        call.ast.params.len + 1 == params.items.len and
+        try builder.analyser.hasSelfParam(decl_handle.handle, fn_proto);
+
+    const parameters = params.items[@intFromBool(has_self_param)..];
+    const arguments = call.ast.params;
+    const min_len = @min(parameters.len, arguments.len);
+    for (parameters[0..min_len], call.ast.params[0..min_len]) |param, arg| {
         const name_token = param.name_token orelse continue;
         const name = decl_tree.tokenSlice(name_token);
 
         if (builder.config.inlay_hints_hide_redundant_param_names or builder.config.inlay_hints_hide_redundant_param_names_last_token) {
-            const last_param_token = tree.lastToken(call.ast.params[i]);
+            const last_arg_token = tree.lastToken(arg);
-            const param_name = tree.tokenSlice(last_param_token);
+            const arg_name = tree.tokenSlice(last_arg_token);
 
-            if (std.mem.eql(u8, param_name, name)) {
+            if (std.mem.eql(u8, arg_name, name)) {
-                if (tree.firstToken(call.ast.params[i]) == last_param_token) {
+                if (tree.firstToken(arg) == last_arg_token) {
                     if (builder.config.inlay_hints_hide_redundant_param_names)
                         continue;
                 } else {
@@ -122,7 +129,7 @@ fn writeCallHint(builder: *Builder, call: Ast.full.Call, decl_handle: Analyser.D
             offsets.nodeToSlice(decl_tree, param.type_expr);
 
         try builder.appendParameterHint(
-            tree.firstToken(call.ast.params[i]),
+            tree.firstToken(arg),
             name,
             tooltip,
             no_alias,

src/stage2/AstGen.zig

@@ -856,10 +856,35 @@ fn expr(gz: *GenZir, scope: *Scope, ri: ResultInfo, node: Ast.Node.Index) InnerE
             return rvalue(gz, ri, result, node);
         },
         .slice => {
+            const extra = tree.extraData(node_datas[node].rhs, Ast.Node.Slice);
+            const lhs_node = node_datas[node].lhs;
+            const lhs_tag = node_tags[lhs_node];
+            const lhs_is_slice_sentinel = lhs_tag == .slice_sentinel;
+            const lhs_is_open_slice = lhs_tag == .slice_open or
+                (lhs_is_slice_sentinel and tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel).end == 0);
+            if (lhs_is_open_slice and nodeIsTriviallyZero(tree, extra.start)) {
+                const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[lhs_node].lhs);
+
+                const start = if (lhs_is_slice_sentinel) start: {
+                    const lhs_extra = tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel);
+                    break :start try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, lhs_extra.start);
+                } else try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, node_datas[lhs_node].rhs);
+
+                const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
+                const len = if (extra.end != 0) try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end) else .none;
+                try emitDbgStmt(gz, cursor);
+                const result = try gz.addPlNode(.slice_length, node, Zir.Inst.SliceLength{
+                    .lhs = lhs,
+                    .start = start,
+                    .len = len,
+                    .start_src_node_offset = gz.nodeIndexToRelative(lhs_node),
+                    .sentinel = .none,
+                });
+                return rvalue(gz, ri, result, node);
+            }
             const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[node].lhs);
 
             const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
-            const extra = tree.extraData(node_datas[node].rhs, Ast.Node.Slice);
             const start = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.start);
             const end = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end);
             try emitDbgStmt(gz, cursor);
@@ -871,10 +896,36 @@ fn expr(gz: *GenZir, scope: *Scope, ri: ResultInfo, node: Ast.Node.Index) InnerE
             return rvalue(gz, ri, result, node);
         },
         .slice_sentinel => {
+            const extra = tree.extraData(node_datas[node].rhs, Ast.Node.SliceSentinel);
+            const lhs_node = node_datas[node].lhs;
+            const lhs_tag = node_tags[lhs_node];
+            const lhs_is_slice_sentinel = lhs_tag == .slice_sentinel;
+            const lhs_is_open_slice = lhs_tag == .slice_open or
+                (lhs_is_slice_sentinel and tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel).end == 0);
+            if (lhs_is_open_slice and nodeIsTriviallyZero(tree, extra.start)) {
+                const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[lhs_node].lhs);
+
+                const start = if (lhs_is_slice_sentinel) start: {
+                    const lhs_extra = tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel);
+                    break :start try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, lhs_extra.start);
+                } else try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, node_datas[lhs_node].rhs);
+
+                const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
+                const len = if (extra.end != 0) try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end) else .none;
+                const sentinel = try expr(gz, scope, .{ .rl = .none }, extra.sentinel);
+                try emitDbgStmt(gz, cursor);
+                const result = try gz.addPlNode(.slice_length, node, Zir.Inst.SliceLength{
+                    .lhs = lhs,
+                    .start = start,
+                    .len = len,
+                    .start_src_node_offset = gz.nodeIndexToRelative(lhs_node),
+                    .sentinel = sentinel,
+                });
+                return rvalue(gz, ri, result, node);
+            }
             const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[node].lhs);
 
             const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
-            const extra = tree.extraData(node_datas[node].rhs, Ast.Node.SliceSentinel);
             const start = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.start);
             const end = if (extra.end != 0) try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end) else .none;
             const sentinel = try expr(gz, scope, .{ .rl = .none }, extra.sentinel);
@@ -1579,7 +1630,7 @@ fn structInitExpr(
 
     if (struct_init.ast.type_expr == 0) {
         if (struct_init.ast.fields.len == 0) {
-            return rvalue(gz, ri, .empty_struct, node);
+            return rvalue(gz, ri, .empty_struct_type, node);
         }
     } else array: {
         const node_tags = tree.nodes.items(.tag);
@@ -2438,7 +2489,7 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
         switch (zir_tags[inst]) {
             // For some instructions, modify the zir data
             // so we can avoid a separate ensure_result_used instruction.
-            .call => {
+            .call, .field_call => {
                 const extra_index = gz.astgen.instructions.items(.data)[inst].pl_node.payload_index;
                 const slot = &gz.astgen.extra.items[extra_index];
                 var flags = @bitCast(Zir.Inst.Call.Flags, slot.*);
@@ -2513,7 +2564,6 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .field_ptr,
             .field_ptr_init,
             .field_val,
-            .field_call_bind,
             .field_ptr_named,
             .field_val_named,
             .func,
@@ -2564,15 +2614,10 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .slice_start,
             .slice_end,
             .slice_sentinel,
+            .slice_length,
             .import,
             .switch_block,
-            .switch_cond,
+            .switch_block_ref,
-            .switch_cond_ref,
-            .switch_capture,
-            .switch_capture_ref,
-            .switch_capture_multi,
-            .switch_capture_multi_ref,
-            .switch_capture_tag,
             .struct_init_empty,
             .struct_init,
             .struct_init_ref,
@@ -2588,15 +2633,15 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .error_set_decl,
             .error_set_decl_anon,
             .error_set_decl_func,
-            .int_to_enum,
+            .enum_from_int,
-            .enum_to_int,
+            .int_from_enum,
             .type_info,
             .size_of,
             .bit_size_of,
             .typeof_log2_int_type,
-            .ptr_to_int,
+            .int_from_ptr,
             .align_of,
-            .bool_to_int,
+            .int_from_bool,
             .embed_file,
             .error_name,
             .sqrt,
@@ -2617,9 +2662,9 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .type_name,
             .frame_type,
             .frame_size,
-            .float_to_int,
+            .int_from_float,
-            .int_to_float,
+            .float_from_int,
-            .int_to_ptr,
+            .ptr_from_int,
             .float_cast,
             .int_cast,
             .ptr_cast,
@@ -2916,7 +2961,7 @@ fn deferStmt(
         try gz.astgen.instructions.append(gz.astgen.gpa, .{
             .tag = .extended,
             .data = .{ .extended = .{
-                .opcode = .errdefer_err_code,
+                .opcode = .value_placeholder,
                 .small = undefined,
                 .operand = undefined,
             } },
@@ -2938,11 +2983,27 @@ fn deferStmt(
     if (have_err_code) try gz.addDbgBlockEnd();
     _ = try defer_gen.addBreak(.break_inline, 0, .void_value);
 
+    // We must handle ref_table for remapped_err_code manually.
     const body = defer_gen.instructionsSlice();
-    const body_len = gz.astgen.countBodyLenAfterFixups(body);
+    const body_len = blk: {
+        var refs: u32 = 0;
+        if (have_err_code) {
+            var cur_inst = remapped_err_code;
+            while (gz.astgen.ref_table.get(cur_inst)) |ref_inst| {
+                refs += 1;
+                cur_inst = ref_inst;
+            }
+        }
+        break :blk gz.astgen.countBodyLenAfterFixups(body) + refs;
+    };
 
     const index = @intCast(u32, gz.astgen.extra.items.len);
     try gz.astgen.extra.ensureUnusedCapacity(gz.astgen.gpa, body_len);
+    if (have_err_code) {
+        if (gz.astgen.ref_table.fetchRemove(remapped_err_code)) |kv| {
+            gz.astgen.appendPossiblyRefdBodyInst(&gz.astgen.extra, kv.value);
+        }
+    }
     gz.astgen.appendBodyWithFixups(body);
 
     const defer_scope = try block_arena.create(Scope.Defer);
@@ -3874,7 +3935,7 @@ fn fnDecl(
     var section_gz = decl_gz.makeSubBlock(params_scope);
     defer section_gz.unstack();
     const section_ref: Zir.Inst.Ref = if (fn_proto.ast.section_expr == 0) .none else inst: {
-        const inst = try expr(&decl_gz, params_scope, .{ .rl = .{ .coerced_ty = .const_slice_u8_type } }, fn_proto.ast.section_expr);
+        const inst = try expr(&decl_gz, params_scope, .{ .rl = .{ .coerced_ty = .slice_const_u8_type } }, fn_proto.ast.section_expr);
         if (section_gz.instructionsSlice().len == 0) {
             // In this case we will send a len=0 body which can be encoded more efficiently.
             break :inst inst;
@@ -3908,9 +3969,9 @@ fn fnDecl(
             break :blk inst;
         } else if (is_extern) {
             // note: https://github.com/ziglang/zig/issues/5269
-            break :blk .calling_convention_c;
+            break :blk .unknown_unknown; // TODO calling_convention_c
         } else if (has_inline_keyword) {
-            break :blk .calling_convention_inline;
+            break :blk .unknown_unknown; // calling_convention_inline
         } else {
             break :blk .none;
         }
@@ -4077,7 +4138,7 @@ fn globalVarDecl(
         break :inst try expr(&block_scope, &block_scope.base, .{ .rl = .{ .ty = .address_space_type } }, var_decl.ast.addrspace_node);
     };
     const section_inst: Zir.Inst.Ref = if (var_decl.ast.section_node == 0) .none else inst: {
-        break :inst try comptimeExpr(&block_scope, &block_scope.base, .{ .rl = .{ .ty = .const_slice_u8_type } }, var_decl.ast.section_node);
+        break :inst try comptimeExpr(&block_scope, &block_scope.base, .{ .rl = .{ .ty = .slice_const_u8_type } }, var_decl.ast.section_node);
     };
     const has_section_or_addrspace = section_inst != .none or addrspace_inst != .none;
     wip_members.nextDecl(is_pub, is_export, align_inst != .none, has_section_or_addrspace);
@@ -4437,7 +4498,7 @@ fn testDecl(
         .cc_gz = null,
         .align_ref = .none,
         .align_gz = null,
-        .ret_ref = .void_type,
+        .ret_ref = .anyerror_void_error_union_type,
         .ret_gz = null,
         .section_ref = .none,
         .section_gz = null,
@@ -4450,7 +4511,7 @@ fn testDecl(
         .body_gz = &fn_block,
         .lib_name = 0,
         .is_var_args = false,
-        .is_inferred_error = true,
+        .is_inferred_error = false,
         .is_test = true,
         .is_extern = false,
         .is_noinline = false,
@@ -6655,6 +6716,7 @@ fn switchExpr(
     // for the following variables, make note of the special prong AST node index,
     // and bail out with a compile error if there are multiple special prongs present.
     var any_payload_is_ref = false;
+    var any_has_tag_capture = false;
     var scalar_cases_len: u32 = 0;
     var multi_cases_len: u32 = 0;
     var inline_cases_len: u32 = 0;
@@ -6665,8 +6727,12 @@ fn switchExpr(
     for (case_nodes) |case_node| {
         const case = tree.fullSwitchCase(case_node).?;
         if (case.payload_token) |payload_token| {
-            if (token_tags[payload_token] == .asterisk) {
+            const ident = if (token_tags[payload_token] == .asterisk) blk: {
                 any_payload_is_ref = true;
+                break :blk payload_token + 1;
+            } else payload_token;
+            if (token_tags[ident + 1] == .comma) {
+                any_has_tag_capture = true;
             }
         }
         // Check for else/`_` prong.
@@ -6775,13 +6841,7 @@ fn switchExpr(
     const operand_lc = LineColumn{ astgen.source_line - parent_gz.decl_line, astgen.source_column };
 
     const raw_operand = try expr(parent_gz, scope, operand_ri, operand_node);
-    const cond_tag: Zir.Inst.Tag = if (any_payload_is_ref) .switch_cond_ref else .switch_cond;
+    const item_ri: ResultInfo = .{ .rl = .none };
-    const cond = try parent_gz.addUnNode(cond_tag, raw_operand, operand_node);
-    // Sema expects a dbg_stmt immediately after switch_cond(_ref)
-    try emitDbgStmt(parent_gz, operand_lc);
-    // We need the type of the operand to use as the result location for all the prong items.
-    const cond_ty_inst = try parent_gz.addUnNode(.typeof, cond, operand_node);
-    const item_ri: ResultInfo = .{ .rl = .{ .ty = cond_ty_inst } };
 
     // This contains the data that goes into the `extra` array for the SwitchBlock/SwitchBlockMulti,
     // except the first cases_nodes.len slots are a table that indexes payloads later in the array, with
@@ -6800,13 +6860,30 @@ fn switchExpr(
     block_scope.instructions_top = GenZir.unstacked_top;
     block_scope.setBreakResultInfo(ri);
 
+    // Sema expects a dbg_stmt immediately before switch_block(_ref)
+    try emitDbgStmt(parent_gz, operand_lc);
     // This gets added to the parent block later, after the item expressions.
-    const switch_block = try parent_gz.makeBlockInst(.switch_block, switch_node);
+    const switch_tag: Zir.Inst.Tag = if (any_payload_is_ref) .switch_block_ref else .switch_block;
+    const switch_block = try parent_gz.makeBlockInst(switch_tag, switch_node);
 
     // We re-use this same scope for all cases, including the special prong, if any.
     var case_scope = parent_gz.makeSubBlock(&block_scope.base);
     case_scope.instructions_top = GenZir.unstacked_top;
 
+    // If any prong has an inline tag capture, allocate a shared dummy instruction for it
+    const tag_inst = if (any_has_tag_capture) tag_inst: {
+        const inst = @intCast(Zir.Inst.Index, astgen.instructions.len);
+        try astgen.instructions.append(astgen.gpa, .{
+            .tag = .extended,
+            .data = .{ .extended = .{
+                .opcode = .value_placeholder,
+                .small = undefined,
+                .operand = undefined,
+            } }, // TODO rename opcode
+        });
+        break :tag_inst inst;
+    } else undefined;
+
     // In this pass we generate all the item and prong expressions.
     var multi_case_index: u32 = 0;
     var scalar_case_index: u32 = 0;
@@ -6820,17 +6897,22 @@ fn switchExpr(
         var dbg_var_inst: Zir.Inst.Ref = undefined;
         var dbg_var_tag_name: ?u32 = null;
         var dbg_var_tag_inst: Zir.Inst.Ref = undefined;
-        var capture_inst: Zir.Inst.Index = 0;
+        var has_tag_capture = false;
-        var tag_inst: Zir.Inst.Index = 0;
         var capture_val_scope: Scope.LocalVal = undefined;
         var tag_scope: Scope.LocalVal = undefined;
+
+        var capture: Zir.Inst.SwitchBlock.ProngInfo.Capture = .none;
+
         const sub_scope = blk: {
             const payload_token = case.payload_token orelse break :blk &case_scope.base;
             const ident = if (token_tags[payload_token] == .asterisk)
                 payload_token + 1
             else
                 payload_token;
+
             const is_ptr = ident != payload_token;
+            capture = if (is_ptr) .by_ref else .by_val;
+
             const ident_slice = tree.tokenSlice(ident);
             var payload_sub_scope: *Scope = undefined;
             if (mem.eql(u8, ident_slice, "_")) {
@@ -6839,53 +6921,18 @@ fn switchExpr(
                 }
                 payload_sub_scope = &case_scope.base;
             } else {
-                if (case_node == special_node) {
-                    const capture_tag: Zir.Inst.Tag = if (is_ptr)
-                        .switch_capture_ref
-                    else
-                        .switch_capture;
-                    capture_inst = @intCast(Zir.Inst.Index, astgen.instructions.len);
-                    try astgen.instructions.append(gpa, .{
-                        .tag = capture_tag,
-                        .data = .{
-                            .switch_capture = .{
-                                .switch_inst = switch_block,
-                                // Max int communicates that this is the else/underscore prong.
-                                .prong_index = std.math.maxInt(u32),
-                            },
-                        },
-                    });
-                } else {
-                    const is_multi_case_bits: u2 = @intFromBool(is_multi_case);
-                    const is_ptr_bits: u2 = @intFromBool(is_ptr);
-                    const capture_tag: Zir.Inst.Tag = switch ((is_multi_case_bits << 1) | is_ptr_bits) {
-                        0b00 => .switch_capture,
-                        0b01 => .switch_capture_ref,
-                        0b10 => .switch_capture_multi,
-                        0b11 => .switch_capture_multi_ref,
-                    };
-                    const capture_index = if (is_multi_case) multi_case_index else scalar_case_index;
-                    capture_inst = @intCast(Zir.Inst.Index, astgen.instructions.len);
-                    try astgen.instructions.append(gpa, .{
-                        .tag = capture_tag,
-                        .data = .{ .switch_capture = .{
-                            .switch_inst = switch_block,
-                            .prong_index = capture_index,
-                        } },
-                    });
-                }
                 const capture_name = try astgen.identAsString(ident);
                 try astgen.detectLocalShadowing(&case_scope.base, capture_name, ident, ident_slice, .capture);
                 capture_val_scope = .{
                     .parent = &case_scope.base,
                     .gen_zir = &case_scope,
                     .name = capture_name,
-                    .inst = indexToRef(capture_inst),
+                    .inst = indexToRef(switch_block),
                     .token_src = payload_token,
                     .id_cat = .capture,
                 };
                 dbg_var_name = capture_name;
-                dbg_var_inst = indexToRef(capture_inst);
+                dbg_var_inst = indexToRef(switch_block);
                 payload_sub_scope = &capture_val_scope.base;
             }
 
@@ -6901,14 +6948,9 @@ fn switchExpr(
             }
             const tag_name = try astgen.identAsString(tag_token);
             try astgen.detectLocalShadowing(payload_sub_scope, tag_name, tag_token, tag_slice, .@"switch tag capture");
-            tag_inst = @intCast(Zir.Inst.Index, astgen.instructions.len);
+
-            try astgen.instructions.append(gpa, .{
+            assert(any_has_tag_capture);
-                .tag = .switch_capture_tag,
+            has_tag_capture = true;
-                .data = .{ .un_tok = .{
-                    .operand = cond,
-                    .src_tok = case_scope.tokenIndexToRelative(tag_token),
-                } },
-            });
 
             tag_scope = .{
                 .parent = payload_sub_scope,
@@ -6974,8 +7016,6 @@ fn switchExpr(
             case_scope.instructions_top = parent_gz.instructions.items.len;
             defer case_scope.unstack();
 
-            if (capture_inst != 0) try case_scope.instructions.append(gpa, capture_inst);
-            if (tag_inst != 0) try case_scope.instructions.append(gpa, tag_inst);
             try case_scope.addDbgBlockBegin();
             if (dbg_var_name) |some| {
                 try case_scope.addDbgVar(.dbg_var_val, some, dbg_var_inst);
@@ -6993,10 +7033,42 @@ fn switchExpr(
             }
 
             const case_slice = case_scope.instructionsSlice();
-            const body_len = astgen.countBodyLenAfterFixups(case_slice);
+            // Since we use the switch_block instruction itself to refer to the
+            // capture, which will not be added to the child block, we need to
+            // handle ref_table manually, and the same for the inline tag
+            // capture instruction.
+            const refs_len = refs: {
+                var n: usize = 0;
+                var check_inst = switch_block;
+                while (astgen.ref_table.get(check_inst)) |ref_inst| {
+                    n += 1;
+                    check_inst = ref_inst;
+                }
+                if (has_tag_capture) {
+                    check_inst = tag_inst;
+                    while (astgen.ref_table.get(check_inst)) |ref_inst| {
+                        n += 1;
+                        check_inst = ref_inst;
+                    }
+                }
+                break :refs n;
+            };
+            const body_len = refs_len + astgen.countBodyLenAfterFixups(case_slice);
             try payloads.ensureUnusedCapacity(gpa, body_len);
-            const inline_bit = @as(u32, @intFromBool(case.inline_token != null)) << 31;
+            payloads.items[body_len_index] = @bitCast(u32, Zir.Inst.SwitchBlock.ProngInfo{
-            payloads.items[body_len_index] = body_len | inline_bit;
+                .body_len = @intCast(u28, body_len),
+                .capture = capture,
+                .is_inline = case.inline_token != null,
+                .has_tag_capture = has_tag_capture,
+            });
+            if (astgen.ref_table.fetchRemove(switch_block)) |kv| {
+                appendPossiblyRefdBodyInst(astgen, payloads, kv.value);
+            }
+            if (has_tag_capture) {
+                if (astgen.ref_table.fetchRemove(tag_inst)) |kv| {
+                    appendPossiblyRefdBodyInst(astgen, payloads, kv.value);
+                }
+            }
             appendBodyWithFixupsArrayList(astgen, payloads, case_slice);
         }
     }
@@ -7005,14 +7077,16 @@ fn switchExpr(
 
     try astgen.extra.ensureUnusedCapacity(gpa, @typeInfo(Zir.Inst.SwitchBlock).Struct.fields.len +
         @intFromBool(multi_cases_len != 0) +
+        @intFromBool(any_has_tag_capture) +
         payloads.items.len - case_table_end);
 
     const payload_index = astgen.addExtraAssumeCapacity(Zir.Inst.SwitchBlock{
-        .operand = cond,
+        .operand = raw_operand,
         .bits = Zir.Inst.SwitchBlock.Bits{
             .has_multi_cases = multi_cases_len != 0,
             .has_else = special_prong == .@"else",
             .has_under = special_prong == .under,
+            .any_has_tag_capture = any_has_tag_capture,
             .scalar_cases_len = @intCast(Zir.Inst.SwitchBlock.Bits.ScalarCasesLen, scalar_cases_len),
         },
     });
@@ -7021,6 +7095,10 @@ fn switchExpr(
         astgen.extra.appendAssumeCapacity(multi_cases_len);
     }
 
+    if (any_has_tag_capture) {
+        astgen.extra.appendAssumeCapacity(tag_inst);
+    }
+
     const zir_datas = astgen.instructions.items(.data);
     const zir_tags = astgen.instructions.items(.tag);
 
@@ -7043,7 +7121,7 @@ fn switchExpr(
             end_index += 3 + items_len + 2 * ranges_len;
         }
 
-        const body_len = @truncate(u31, payloads.items[body_len_index]);
+        const body_len = @bitCast(Zir.Inst.SwitchBlock.ProngInfo, payloads.items[body_len_index]).body_len;
         end_index += body_len;
 
         switch (strat.tag) {
@@ -7818,7 +7896,7 @@ fn unionInit(
     params: []const Ast.Node.Index,
 ) InnerError!Zir.Inst.Ref {
     const union_type = try typeExpr(gz, scope, params[0]);
-    const field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[1]);
+    const field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[1]);
     const field_type = try gz.addPlNode(.field_type_ref, params[1], Zir.Inst.FieldTypeRef{
         .container_type = union_type,
         .field_name = field_name,
@@ -8040,12 +8118,12 @@ fn builtinCall(
             if (ri.rl == .ref) {
                 return gz.addPlNode(.field_ptr_named, node, Zir.Inst.FieldNamed{
                     .lhs = try expr(gz, scope, .{ .rl = .ref }, params[0]),
-                    .field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[1]),
+                    .field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[1]),
                 });
             }
             const result = try gz.addPlNode(.field_val_named, node, Zir.Inst.FieldNamed{
                 .lhs = try expr(gz, scope, .{ .rl = .none }, params[0]),
-                .field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[1]),
+                .field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[1]),
             });
             return rvalue(gz, ri, result, node);
         },
@@ -8210,12 +8288,12 @@ fn builtinCall(
         .bit_size_of => return simpleUnOpType(gz, scope, ri, node, params[0], .bit_size_of),
         .align_of    => return simpleUnOpType(gz, scope, ri, node, params[0], .align_of),
 
-        .ptr_to_int            => return simpleUnOp(gz, scope, ri, node, .{ .rl = .none },                           params[0], .ptr_to_int),
+        .int_from_ptr            => return simpleUnOp(gz, scope, ri, node, .{ .rl = .none },                           params[0], .int_from_ptr),
-        .compile_error         => return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[0], .compile_error),
+        .compile_error         => return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[0], .compile_error),
         .set_eval_branch_quota => return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .coerced_ty = .u32_type } },    params[0], .set_eval_branch_quota),
-        .enum_to_int           => return simpleUnOp(gz, scope, ri, node, .{ .rl = .none },                           params[0], .enum_to_int),
+        .int_from_enum           => return simpleUnOp(gz, scope, ri, node, .{ .rl = .none },                           params[0], .int_from_enum),
-        .bool_to_int           => return simpleUnOp(gz, scope, ri, node, bool_ri,                                    params[0], .bool_to_int),
+        .int_from_bool           => return simpleUnOp(gz, scope, ri, node, bool_ri,                                    params[0], .int_from_bool),
-        .embed_file            => return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[0], .embed_file),
+        .embed_file            => return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[0], .embed_file),
         .error_name            => return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .ty = .anyerror_type } },       params[0], .error_name),
         .set_runtime_safety    => return simpleUnOp(gz, scope, ri, node, bool_ri,                                    params[0], .set_runtime_safety),
         .sqrt                  => return simpleUnOp(gz, scope, ri, node, .{ .rl = .none },                           params[0], .sqrt),
@@ -8237,10 +8315,10 @@ fn builtinCall(
         .Frame                 => return simpleUnOp(gz, scope, ri, node, .{ .rl = .none },                           params[0], .frame_type),
         .frame_size            => return simpleUnOp(gz, scope, ri, node, .{ .rl = .none },                           params[0], .frame_size),
 
-        .float_to_int => return typeCast(gz, scope, ri, node, params[0], params[1], .float_to_int),
+        .int_from_float => return typeCast(gz, scope, ri, node, params[0], params[1], .int_from_float),
-        .int_to_float => return typeCast(gz, scope, ri, node, params[0], params[1], .int_to_float),
+        .float_from_int => return typeCast(gz, scope, ri, node, params[0], params[1], .float_from_int),
-        .int_to_ptr   => return typeCast(gz, scope, ri, node, params[0], params[1], .int_to_ptr),
+        .ptr_from_int   => return typeCast(gz, scope, ri, node, params[0], params[1], .ptr_from_int),
-        .int_to_enum  => return typeCast(gz, scope, ri, node, params[0], params[1], .int_to_enum),
+        .enum_from_int  => return typeCast(gz, scope, ri, node, params[0], params[1], .enum_from_int),
         .float_cast   => return typeCast(gz, scope, ri, node, params[0], params[1], .float_cast),
         .int_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .int_cast),
         .ptr_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .ptr_cast),
@@ -8274,24 +8352,24 @@ fn builtinCall(
         },
         .panic => {
             try emitDbgNode(gz, node);
-            return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[0], .panic);
+            return simpleUnOp(gz, scope, ri, node, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[0], .panic);
         },
         .trap => {
             try emitDbgNode(gz, node);
             _ = try gz.addNode(.trap, node);
-            return rvalue(gz, ri, .void_value, node);
+            return rvalue(gz, ri, .unreachable_value, node);
         },
-        .error_to_int => {
+        .int_from_error => {
             const operand = try expr(gz, scope, .{ .rl = .none }, params[0]);
-            const result = try gz.addExtendedPayload(.error_to_int, Zir.Inst.UnNode{
+            const result = try gz.addExtendedPayload(.int_from_error, Zir.Inst.UnNode{
                 .node = gz.nodeIndexToRelative(node),
                 .operand = operand,
             });
             return rvalue(gz, ri, result, node);
         },
-        .int_to_error => {
+        .error_from_int => {
             const operand = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .u16_type } }, params[0]);
-            const result = try gz.addExtendedPayload(.int_to_error, Zir.Inst.UnNode{
+            const result = try gz.addExtendedPayload(.error_from_int, Zir.Inst.UnNode{
                 .node = gz.nodeIndexToRelative(node),
                 .operand = operand,
             });
@@ -8390,7 +8468,7 @@ fn builtinCall(
         },
         .c_define => {
             if (!gz.c_import) return gz.astgen.failNode(node, "C define valid only inside C import block", .{});
-            const name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[0]);
+            const name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[0]);
             const value = try comptimeExpr(gz, scope, .{ .rl = .none }, params[1]);
             const result = try gz.addExtendedPayload(.c_define, Zir.Inst.BinNode{
                 .node = gz.nodeIndexToRelative(node),
@@ -8470,8 +8548,8 @@ fn builtinCall(
             return rvalue(gz, ri, result, node);
         },
         .call => {
-            const modifier = try comptimeExpr(gz, scope, .{ .rl = .{ .coerced_ty = .modifier_type } }, params[0]);
+            const modifier = try comptimeExpr(gz, scope, .{ .rl = .{ .coerced_ty = .call_modifier_type } }, params[0]);
-            const callee = try calleeExpr(gz, scope, params[1]);
+            const callee = try expr(gz, scope, .{ .rl = .none }, params[1]);
             const args = try expr(gz, scope, .{ .rl = .none }, params[2]);
             const result = try gz.addPlNode(.builtin_call, node, Zir.Inst.BuiltinCall{
                 .modifier = modifier,
@@ -8486,7 +8564,7 @@ fn builtinCall(
         },
         .field_parent_ptr => {
             const parent_type = try typeExpr(gz, scope, params[0]);
-            const field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[1]);
+            const field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, params[1]);
             const result = try gz.addPlNode(.field_parent_ptr, node, Zir.Inst.FieldParentPtr{
                 .parent_type = parent_type,
                 .field_name = field_name,
@@ -8641,7 +8719,7 @@ fn hasDeclOrField(
     tag: Zir.Inst.Tag,
 ) InnerError!Zir.Inst.Ref {
     const container_type = try typeExpr(gz, scope, lhs_node);
-    const name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, rhs_node);
+    const name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, rhs_node);
     const result = try gz.addPlNode(tag, node, Zir.Inst.Bin{
         .lhs = container_type,
         .rhs = name,
@@ -8698,7 +8776,7 @@ fn simpleUnOp(
     else
         try expr(gz, scope, operand_ri, operand_node);
     switch (tag) {
-        .tag_name, .error_name, .ptr_to_int => try emitDbgStmt(gz, cursor),
+        .tag_name, .error_name, .int_from_ptr => try emitDbgStmt(gz, cursor),
         else => {},
     }
     const result = try gz.addUnNode(tag, operand, node);
@@ -8791,7 +8869,7 @@ fn simpleCBuiltin(
 ) InnerError!Zir.Inst.Ref {
     const name: []const u8 = if (tag == .c_undef) "C undef" else "C include";
     if (!gz.c_import) return gz.astgen.failNode(node, "{s} valid only inside C import block", .{name});
-    const operand = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, operand_node);
+    const operand = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, operand_node);
     _ = try gz.addExtendedPayload(tag, Zir.Inst.UnNode{
         .node = gz.nodeIndexToRelative(node),
         .operand = operand,
@@ -8809,7 +8887,7 @@ fn offsetOf(
     tag: Zir.Inst.Tag,
 ) InnerError!Zir.Inst.Ref {
     const type_inst = try typeExpr(gz, scope, lhs_node);
-    const field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, rhs_node);
+    const field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .slice_const_u8_type } }, rhs_node);
     const result = try gz.addPlNode(tag, node, Zir.Inst.Bin{
         .lhs = type_inst,
         .rhs = field_name,
@@ -8931,7 +9009,10 @@ fn callExpr(
         } });
     }
 
-    assert(callee != .none);
+    switch (callee) {
+        .direct => |obj| assert(obj != .none),
+        .field => |field| assert(field.obj_ptr != .none),
+    }
     assert(node != 0);
 
     const call_index = @intCast(Zir.Inst.Index, astgen.instructions.len);
@@ -8970,89 +9051,98 @@ fn callExpr(
         else => false,
     };
 
-    const payload_index = try addExtra(astgen, Zir.Inst.Call{
+    switch (callee) {
-        .callee = callee,
+        .direct => |callee_obj| {
-        .flags = .{
+            const payload_index = try addExtra(astgen, Zir.Inst.Call{
-            .pop_error_return_trace = !propagate_error_trace,
+                .callee = callee_obj,
-            .packed_modifier = @intCast(Zir.Inst.Call.Flags.PackedModifier, @intFromEnum(modifier)),
+                .flags = .{
-            .args_len = @intCast(Zir.Inst.Call.Flags.PackedArgsLen, call.ast.params.len),
+                    .pop_error_return_trace = !propagate_error_trace,
+                    .packed_modifier = @intCast(Zir.Inst.Call.Flags.PackedModifier, @intFromEnum(modifier)),
+                    .args_len = @intCast(Zir.Inst.Call.Flags.PackedArgsLen, call.ast.params.len),
+                },
+            });
+            if (call.ast.params.len != 0) {
+                try astgen.extra.appendSlice(astgen.gpa, astgen.scratch.items[scratch_top..]);
+            }
+            gz.astgen.instructions.set(call_index, .{
+                .tag = .call,
+                .data = .{ .pl_node = .{
+                    .src_node = gz.nodeIndexToRelative(node),
+                    .payload_index = payload_index,
+                } },
+            });
+        },
+        .field => |callee_field| {
+            const payload_index = try addExtra(astgen, Zir.Inst.FieldCall{
+                .obj_ptr = callee_field.obj_ptr,
+                .field_name_start = callee_field.field_name_start,
+                .flags = .{
+                    .pop_error_return_trace = !propagate_error_trace,
+                    .packed_modifier = @intCast(Zir.Inst.Call.Flags.PackedModifier, @intFromEnum(modifier)),
+                    .args_len = @intCast(Zir.Inst.Call.Flags.PackedArgsLen, call.ast.params.len),
+                },
+            });
+            if (call.ast.params.len != 0) {
+                try astgen.extra.appendSlice(astgen.gpa, astgen.scratch.items[scratch_top..]);
+            }
+            gz.astgen.instructions.set(call_index, .{
+                .tag = .field_call,
+                .data = .{ .pl_node = .{
+                    .src_node = gz.nodeIndexToRelative(node),
+                    .payload_index = payload_index,
+                } },
+            });
         },
-    });
-    if (call.ast.params.len != 0) {
-        try astgen.extra.appendSlice(astgen.gpa, astgen.scratch.items[scratch_top..]);
     }
-    gz.astgen.instructions.set(call_index, .{
-        .tag = .call,
-        .data = .{ .pl_node = .{
-            .src_node = gz.nodeIndexToRelative(node),
-            .payload_index = payload_index,
-        } },
-    });
     return rvalue(gz, ri, call_inst, node); // TODO function call with result location
 }
 
-/// calleeExpr generates the function part of a call expression (f in f(x)), or the
+const Callee = union(enum) {
-/// callee argument to the @call() builtin. If the lhs is a field access or the
+    field: struct {
-/// @field() builtin, we need to generate a special field_call_bind instruction
+        /// A *pointer* to the object the field is fetched on, so that we can
-/// instead of the normal field_val or field_ptr.  If this is a inst.func() call,
+        /// promote the lvalue to an address if the first parameter requires it.
-/// this instruction will capture the value of the first argument before evaluating
+        obj_ptr: Zir.Inst.Ref,
-/// the other arguments. We need to use .ref here to guarantee we will be able to
+        /// Offset into `string_bytes`.
-/// promote an lvalue to an address if the first parameter requires it.  This
+        field_name_start: u32,
-/// unfortunately also means we need to take a reference to any types on the lhs.
+    },
+    direct: Zir.Inst.Ref,
+};
+
+/// calleeExpr generates the function part of a call expression (f in f(x)), but
+/// *not* the callee argument to the @call() builtin. Its purpose is to
+/// distinguish between standard calls and method call syntax `a.b()`. Thus, if
+/// the lhs is a field access, we return using the `field` union field;
+/// otherwise, we use the `direct` union field.
 fn calleeExpr(
     gz: *GenZir,
     scope: *Scope,
     node: Ast.Node.Index,
-) InnerError!Zir.Inst.Ref {
+) InnerError!Callee {
     const astgen = gz.astgen;
     const tree = astgen.tree;
 
     const tag = tree.nodes.items(.tag)[node];
     switch (tag) {
-        .field_access => return addFieldAccess(.field_call_bind, gz, scope, .{ .rl = .ref }, node),
+        .field_access => {
-
-        .builtin_call_two,
-        .builtin_call_two_comma,
-        .builtin_call,
-        .builtin_call_comma,
-        => {
-            const node_datas = tree.nodes.items(.data);
             const main_tokens = tree.nodes.items(.main_token);
-            const builtin_token = main_tokens[node];
+            const node_datas = tree.nodes.items(.data);
-            const builtin_name = tree.tokenSlice(builtin_token);
+            const object_node = node_datas[node].lhs;
+            const dot_token = main_tokens[node];
+            const field_ident = dot_token + 1;
+            const str_index = try astgen.identAsString(field_ident);
+            // Capture the object by reference so we can promote it to an
+            // address in Sema if needed.
+            const lhs = try expr(gz, scope, .{ .rl = .ref }, object_node);
 
-            var inline_params: [2]Ast.Node.Index = undefined;
+            const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
-            var params: []Ast.Node.Index = switch (tag) {
+            try emitDbgStmt(gz, cursor);
-                .builtin_call,
-                .builtin_call_comma,
-                => tree.extra_data[node_datas[node].lhs..node_datas[node].rhs],
 
-                .builtin_call_two,
+            return .{ .field = .{
-                .builtin_call_two_comma,
+                .obj_ptr = lhs,
-                => blk: {
+                .field_name_start = str_index,
-                    inline_params = .{ node_datas[node].lhs, node_datas[node].rhs };
+            } };
-                    const len: usize = if (inline_params[0] == 0) @as(usize, 0) else if (inline_params[1] == 0) @as(usize, 1) else @as(usize, 2);
-                    break :blk inline_params[0..len];
-                },
-
-                else => unreachable,
-            };
-
-            // If anything is wrong, fall back to builtinCall.
-            // It will emit any necessary compile errors and notes.
-            if (std.mem.eql(u8, builtin_name, "@field") and params.len == 2) {
-                const lhs = try expr(gz, scope, .{ .rl = .ref }, params[0]);
-                const field_name = try comptimeExpr(gz, scope, .{ .rl = .{ .ty = .const_slice_u8_type } }, params[1]);
-                return gz.addExtendedPayload(.field_call_bind_named, Zir.Inst.FieldNamedNode{
-                    .node = gz.nodeIndexToRelative(node),
-                    .lhs = lhs,
-                    .field_name = field_name,
-                });
-            }
-
-            return builtinCall(gz, scope, .{ .rl = .none }, node, params);
         },
-        else => return expr(gz, scope, .{ .rl = .none }, node),
+        else => return .{ .direct = try expr(gz, scope, .{ .rl = .none }, node) },
     }
 }
 
@@ -10199,6 +10289,8 @@ fn rvalue(
                 as_ty | @intFromEnum(Zir.Inst.Ref.i32_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.u64_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.i64_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.u128_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.i128_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.usize_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.isize_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.c_char_type),
@@ -10224,15 +10316,30 @@ fn rvalue(
                 as_ty | @intFromEnum(Zir.Inst.Ref.comptime_int_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.comptime_float_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.noreturn_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.anyframe_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.null_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.undefined_type),
-                as_ty | @intFromEnum(Zir.Inst.Ref.fn_noreturn_no_args_type),
-                as_ty | @intFromEnum(Zir.Inst.Ref.fn_void_no_args_type),
-                as_ty | @intFromEnum(Zir.Inst.Ref.fn_naked_noreturn_no_args_type),
-                as_ty | @intFromEnum(Zir.Inst.Ref.fn_ccc_void_no_args_type),
-                as_ty | @intFromEnum(Zir.Inst.Ref.single_const_pointer_to_comptime_int_type),
-                as_ty | @intFromEnum(Zir.Inst.Ref.const_slice_u8_type),
                 as_ty | @intFromEnum(Zir.Inst.Ref.enum_literal_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.atomic_order_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.atomic_rmw_op_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.calling_convention_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.address_space_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.float_mode_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.reduce_op_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.call_modifier_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.prefetch_options_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.export_options_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.extern_options_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.type_info_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.manyptr_u8_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.manyptr_const_u8_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.manyptr_const_u8_sentinel_0_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.single_const_pointer_to_comptime_int_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.slice_const_u8_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.slice_const_u8_sentinel_0_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.anyerror_void_error_union_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.generic_poison_type),
+                as_ty | @intFromEnum(Zir.Inst.Ref.empty_struct_type),
                 as_comptime_int | @intFromEnum(Zir.Inst.Ref.zero),
                 as_comptime_int | @intFromEnum(Zir.Inst.Ref.one),
                 as_bool | @intFromEnum(Zir.Inst.Ref.bool_true),
@@ -10605,8 +10712,8 @@ fn identAsString(astgen: *AstGen, ident_token: Ast.TokenIndex) !u32 {
     const string_bytes = &astgen.string_bytes;
     const str_index = @intCast(u32, string_bytes.items.len);
     try astgen.appendIdentStr(ident_token, string_bytes);
-    const key = string_bytes.items[str_index..];
+    const key: []const u8 = string_bytes.items[str_index..];
-    const gop = try astgen.string_table.getOrPutContextAdapted(gpa, @as([]const u8, key), StringIndexAdapter{
+    const gop = try astgen.string_table.getOrPutContextAdapted(gpa, key, StringIndexAdapter{
         .bytes = string_bytes,
     }, StringIndexContext{
         .bytes = string_bytes,
@@ -11689,9 +11796,9 @@ const GenZir = struct {
     ) !Zir.Inst.Index {
         const gpa = gz.astgen.gpa;
         const param_body = param_gz.instructionsSlice();
+        const body_len = gz.astgen.countBodyLenAfterFixups(param_body);
         try gz.astgen.instructions.ensureUnusedCapacity(gpa, 1);
-        try gz.astgen.extra.ensureUnusedCapacity(gpa, @typeInfo(Zir.Inst.Param).Struct.fields.len +
+        try gz.astgen.extra.ensureUnusedCapacity(gpa, @typeInfo(Zir.Inst.Param).Struct.fields.len + body_len);
-            param_body.len);
 
         const doc_comment_index = if (first_doc_comment) |first|
             try gz.astgen.docCommentAsStringFromFirst(abs_tok_index, first)
@@ -11701,9 +11808,9 @@ const GenZir = struct {
         const payload_index = gz.astgen.addExtraAssumeCapacity(Zir.Inst.Param{
             .name = name,
             .doc_comment = doc_comment_index,
-            .body_len = @intCast(u32, param_body.len),
+            .body_len = @intCast(u32, body_len),
         });
-        gz.astgen.extra.appendSliceAssumeCapacity(param_body);
+        gz.astgen.appendBodyWithFixups(param_body);
         param_gz.unstack();
 
         const new_index = @intCast(Zir.Inst.Index, gz.astgen.instructions.len);

src/stage2/BuiltinFn.zig

@@ -12,7 +12,7 @@ pub const Tag = enum {
     atomic_store,
     bit_cast,
     bit_offset_of,
-    bool_to_int,
+    int_from_bool,
     bit_size_of,
     breakpoint,
     mul_add,
@@ -39,10 +39,10 @@ pub const Tag = enum {
     div_floor,
     div_trunc,
     embed_file,
-    enum_to_int,
+    int_from_enum,
     error_name,
     error_return_trace,
-    error_to_int,
+    int_from_error,
     err_set_cast,
     @"export",
     @"extern",
@@ -50,7 +50,7 @@ pub const Tag = enum {
     field,
     field_parent_ptr,
     float_cast,
-    float_to_int,
+    int_from_float,
     frame,
     Frame,
     frame_address,
@@ -60,10 +60,10 @@ pub const Tag = enum {
     import,
     in_comptime,
     int_cast,
-    int_to_enum,
+    enum_from_int,
-    int_to_error,
+    error_from_int,
-    int_to_float,
+    float_from_int,
-    int_to_ptr,
+    ptr_from_int,
     max,
     memcpy,
     memset,
@@ -76,7 +76,7 @@ pub const Tag = enum {
     pop_count,
     prefetch,
     ptr_cast,
-    ptr_to_int,
+    int_from_ptr,
     rem,
     return_address,
     select,
@@ -238,9 +238,9 @@ pub const list = list: {
             },
         },
         .{
-            "@boolToInt",
+            "@intFromBool",
             .{
-                .tag = .bool_to_int,
+                .tag = .int_from_bool,
                 .param_count = 1,
             },
         },
@@ -425,9 +425,9 @@ pub const list = list: {
             },
         },
         .{
-            "@enumToInt",
+            "@intFromEnum",
             .{
-                .tag = .enum_to_int,
+                .tag = .int_from_enum,
                 .param_count = 1,
             },
         },
@@ -446,9 +446,9 @@ pub const list = list: {
             },
         },
         .{
-            "@errorToInt",
+            "@intFromError",
             .{
-                .tag = .error_to_int,
+                .tag = .int_from_error,
                 .param_count = 1,
             },
         },
@@ -506,9 +506,9 @@ pub const list = list: {
             },
         },
         .{
-            "@floatToInt",
+            "@intFromFloat",
             .{
-                .tag = .float_to_int,
+                .tag = .int_from_float,
                 .param_count = 2,
             },
         },
@@ -576,31 +576,31 @@ pub const list = list: {
             },
         },
         .{
-            "@intToEnum",
+            "@enumFromInt",
             .{
-                .tag = .int_to_enum,
+                .tag = .enum_from_int,
                 .param_count = 2,
             },
         },
         .{
-            "@intToError",
+            "@errorFromInt",
             .{
-                .tag = .int_to_error,
+                .tag = .error_from_int,
                 .eval_to_error = .always,
                 .param_count = 1,
             },
         },
         .{
-            "@intToFloat",
+            "@floatFromInt",
             .{
-                .tag = .int_to_float,
+                .tag = .float_from_int,
                 .param_count = 2,
             },
         },
         .{
-            "@intToPtr",
+            "@ptrFromInt",
             .{
-                .tag = .int_to_ptr,
+                .tag = .ptr_from_int,
                 .param_count = 2,
             },
         },
@@ -689,9 +689,9 @@ pub const list = list: {
             },
         },
         .{
-            "@ptrToInt",
+            "@intFromPtr",
             .{
-                .tag = .ptr_to_int,
+                .tag = .int_from_ptr,
                 .param_count = 1,
             },
         },

src/stage2/Zir.zig

@@ -19,6 +19,7 @@ const BigIntConst = std.math.big.int.Const;
 const BigIntMutable = std.math.big.int.Mutable;
 const Ast = std.zig.Ast;
 
+const InternPool = @import("../analyser/InternPool.zig");
 const Zir = @This();
 const Module = @import("Module.zig");
 const LazySrcLoc = Module.LazySrcLoc;
@@ -294,6 +295,14 @@ pub const Inst = struct {
         /// Uses the `pl_node` union field with payload `Call`.
         /// AST node is the function call.
         call,
+        /// Function call using `a.b()` syntax.
+        /// Uses the named field as the callee. If there is no such field, searches in the type for
+        /// a decl matching the field name. The decl is resolved and we ensure that it's a function
+        /// which can accept the object as the first parameter, with one pointer fixup. This
+        /// function is then used as the callee, with the object as an implicit first parameter.
+        /// Uses the `pl_node` union field with payload `FieldCall`.
+        /// AST node is the function call.
+        field_call,
         /// Implements the `@call` builtin.
         /// Uses the `pl_node` union field with payload `BuiltinCall`.
         /// AST node is the builtin call.
@@ -429,15 +438,6 @@ pub const Inst = struct {
         /// This instruction also accepts a pointer.
         /// Uses `pl_node` field. The AST node is the a.b syntax. Payload is Field.
         field_val,
-        /// Given a pointer to a struct or object that contains virtual fields, returns the
-        /// named field.  If there is no named field, searches in the type for a decl that
-        /// matches the field name.  The decl is resolved and we ensure that it's a function
-        /// which can accept the object as the first parameter, with one pointer fixup.  If
-        /// all of that works, this instruction produces a special "bound function" value
-        /// which contains both the function and the saved first parameter value.
-        /// Bound functions may only be used as the function parameter to a `call` or
-        /// `builtin_call` instruction.  Any other use is invalid zir and may crash the compiler.
-        field_call_bind,
         /// Given a pointer to a struct or object that contains virtual fields, returns a pointer
         /// to the named field. The field name is a comptime instruction. Used by @field.
         /// Uses `pl_node` field. The AST node is the builtin call. Payload is FieldNamed.
@@ -567,6 +567,10 @@ pub const Inst = struct {
         /// Returns a pointer to the subslice.
         /// Uses the `pl_node` field. AST node is the slice syntax. Payload is `SliceSentinel`.
         slice_sentinel,
+        /// Slice operation `array_ptr[start..][0..len]`. Optional sentinel.
+        /// Returns a pointer to the subslice.
+        /// Uses the `pl_node` field. AST node is the slice syntax. Payload is `SliceLength`.
+        slice_length,
         /// Write a value to a pointer. For loading, see `load`.
         /// Source location is assumed to be same as previous instruction.
         /// Uses the `bin` union field.
@@ -660,38 +664,9 @@ pub const Inst = struct {
         /// A switch expression. Uses the `pl_node` union field.
         /// AST node is the switch, payload is `SwitchBlock`.
         switch_block,
-        /// Produces the value that will be switched on. For example, for
+        /// A switch expression. Uses the `pl_node` union field.
-        /// integers, it returns the integer with no modifications. For tagged unions, it
+        /// AST node is the switch, payload is `SwitchBlock`. Operand is a pointer.
-        /// returns the active enum tag.
+        switch_block_ref,
-        /// Uses the `un_node` union field.
-        switch_cond,
-        /// Same as `switch_cond`, except the input operand is a pointer to
-        /// what will be switched on.
-        /// Uses the `un_node` union field.
-        switch_cond_ref,
-        /// Produces the capture value for a switch prong.
-        /// Uses the `switch_capture` field.
-        /// If the `prong_index` field is max int, it means this is the capture
-        /// for the else/`_` prong.
-        switch_capture,
-        /// Produces the capture value for a switch prong.
-        /// Result is a pointer to the value.
-        /// Uses the `switch_capture` field.
-        /// If the `prong_index` field is max int, it means this is the capture
-        /// for the else/`_` prong.
-        switch_capture_ref,
-        /// Produces the capture value for a switch prong.
-        /// The prong is one of the multi cases.
-        /// Uses the `switch_capture` field.
-        switch_capture_multi,
-        /// Produces the capture value for a switch prong.
-        /// The prong is one of the multi cases.
-        /// Result is a pointer to the value.
-        /// Uses the `switch_capture` field.
-        switch_capture_multi_ref,
-        /// Produces the capture value for an inline switch prong tag capture.
-        /// Uses the `un_tok` field.
-        switch_capture_tag,
         /// Given a
         ///   *A returns *A
         ///   *E!A returns *A
@@ -771,9 +746,9 @@ pub const Inst = struct {
         /// Implements the `@bitSizeOf` builtin. Uses `un_node`.
         bit_size_of,
 
-        /// Implement builtin `@ptrToInt`. Uses `un_node`.
+        /// Implement builtin `@intFromPtr`. Uses `un_node`.
         /// Convert a pointer to a `usize` integer.
-        ptr_to_int,
+        int_from_ptr,
         /// Emit an error message and fail compilation.
         /// Uses the `un_node` field.
         compile_error,
@@ -783,11 +758,11 @@ pub const Inst = struct {
         set_eval_branch_quota,
         /// Converts an enum value into an integer. Resulting type will be the tag type
         /// of the enum. Uses `un_node`.
-        enum_to_int,
+        int_from_enum,
         /// Implement builtin `@alignOf`. Uses `un_node`.
         align_of,
-        /// Implement builtin `@boolToInt`. Uses `un_node`.
+        /// Implement builtin `@intFromBool`. Uses `un_node`.
-        bool_to_int,
+        int_from_bool,
         /// Implement builtin `@embedFile`. Uses `un_node`.
         embed_file,
         /// Implement builtin `@errorName`. Uses `un_node`.
@@ -836,18 +811,18 @@ pub const Inst = struct {
         /// Implement builtin `@frameSize`. Uses `un_node`.
         frame_size,
 
-        /// Implements the `@floatToInt` builtin.
+        /// Implements the `@intFromFloat` builtin.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
-        float_to_int,
+        int_from_float,
-        /// Implements the `@intToFloat` builtin.
+        /// Implements the `@floatFromInt` builtin.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
-        int_to_float,
+        float_from_int,
-        /// Implements the `@intToPtr` builtin.
+        /// Implements the `@ptrFromInt` builtin.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
-        int_to_ptr,
+        ptr_from_int,
         /// Converts an integer into an enum value.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
-        int_to_enum,
+        enum_from_int,
         /// Convert a larger float type to any other float type, possibly causing
         /// a loss of precision.
         /// Uses the `pl_node` field. AST is the `@floatCast` syntax.
@@ -1044,6 +1019,7 @@ pub const Inst = struct {
                 .bool_br_or,
                 .bool_not,
                 .call,
+                .field_call,
                 .cmp_lt,
                 .cmp_lte,
                 .cmp_eq,
@@ -1076,7 +1052,6 @@ pub const Inst = struct {
                 .field_ptr,
                 .field_ptr_init,
                 .field_val,
-                .field_call_bind,
                 .field_ptr_named,
                 .field_val_named,
                 .func,
@@ -1132,18 +1107,13 @@ pub const Inst = struct {
                 .slice_start,
                 .slice_end,
                 .slice_sentinel,
+                .slice_length,
                 .import,
                 .typeof_log2_int_type,
                 .resolve_inferred_alloc,
                 .set_eval_branch_quota,
-                .switch_capture,
-                .switch_capture_ref,
-                .switch_capture_multi,
-                .switch_capture_multi_ref,
-                .switch_capture_tag,
                 .switch_block,
-                .switch_cond,
+                .switch_block_ref,
-                .switch_cond_ref,
                 .array_base_ptr,
                 .field_base_ptr,
                 .validate_array_init_ty,
@@ -1163,14 +1133,14 @@ pub const Inst = struct {
                 .union_init,
                 .field_type,
                 .field_type_ref,
-                .int_to_enum,
+                .enum_from_int,
-                .enum_to_int,
+                .int_from_enum,
                 .type_info,
                 .size_of,
                 .bit_size_of,
-                .ptr_to_int,
+                .int_from_ptr,
                 .align_of,
-                .bool_to_int,
+                .int_from_bool,
                 .embed_file,
                 .error_name,
                 .set_runtime_safety,
@@ -1192,9 +1162,9 @@ pub const Inst = struct {
                 .type_name,
                 .frame_type,
                 .frame_size,
-                .float_to_int,
+                .int_from_float,
-                .int_to_float,
+                .float_from_int,
-                .int_to_ptr,
+                .ptr_from_int,
                 .float_cast,
                 .int_cast,
                 .ptr_cast,
@@ -1353,6 +1323,7 @@ pub const Inst = struct {
                 .bool_br_or,
                 .bool_not,
                 .call,
+                .field_call,
                 .cmp_lt,
                 .cmp_lte,
                 .cmp_eq,
@@ -1375,7 +1346,6 @@ pub const Inst = struct {
                 .field_ptr,
                 .field_ptr_init,
                 .field_val,
-                .field_call_bind,
                 .field_ptr_named,
                 .field_val_named,
                 .func,
@@ -1427,16 +1397,11 @@ pub const Inst = struct {
                 .slice_start,
                 .slice_end,
                 .slice_sentinel,
+                .slice_length,
                 .import,
                 .typeof_log2_int_type,
-                .switch_capture,
-                .switch_capture_ref,
-                .switch_capture_multi,
-                .switch_capture_multi_ref,
-                .switch_capture_tag,
                 .switch_block,
-                .switch_cond,
+                .switch_block_ref,
-                .switch_cond_ref,
                 .array_base_ptr,
                 .field_base_ptr,
                 .struct_init_empty,
@@ -1451,14 +1416,14 @@ pub const Inst = struct {
                 .union_init,
                 .field_type,
                 .field_type_ref,
-                .int_to_enum,
+                .enum_from_int,
-                .enum_to_int,
+                .int_from_enum,
                 .type_info,
                 .size_of,
                 .bit_size_of,
-                .ptr_to_int,
+                .int_from_ptr,
                 .align_of,
-                .bool_to_int,
+                .int_from_bool,
                 .embed_file,
                 .error_name,
                 .sqrt,
@@ -1479,9 +1444,9 @@ pub const Inst = struct {
                 .type_name,
                 .frame_type,
                 .frame_size,
-                .float_to_int,
+                .int_from_float,
-                .int_to_float,
+                .float_from_int,
-                .int_to_ptr,
+                .ptr_from_int,
                 .float_cast,
                 .int_cast,
                 .ptr_cast,
@@ -1592,6 +1557,7 @@ pub const Inst = struct {
                 .check_comptime_control_flow = .un_node,
                 .for_len = .pl_node,
                 .call = .pl_node,
+                .field_call = .pl_node,
                 .cmp_lt = .pl_node,
                 .cmp_lte = .pl_node,
                 .cmp_eq = .pl_node,
@@ -1632,7 +1598,6 @@ pub const Inst = struct {
                 .field_val = .pl_node,
                 .field_ptr_named = .pl_node,
                 .field_val_named = .pl_node,
-                .field_call_bind = .pl_node,
                 .func = .pl_node,
                 .func_inferred = .pl_node,
                 .func_fancy = .pl_node,
@@ -1664,6 +1629,7 @@ pub const Inst = struct {
                 .slice_start = .pl_node,
                 .slice_end = .pl_node,
                 .slice_sentinel = .pl_node,
+                .slice_length = .pl_node,
                 .store = .bin,
                 .store_node = .pl_node,
                 .store_to_block_ptr = .bin,
@@ -1686,13 +1652,7 @@ pub const Inst = struct {
                 .err_union_code_ptr = .un_node,
                 .enum_literal = .str_tok,
                 .switch_block = .pl_node,
-                .switch_cond = .un_node,
+                .switch_block_ref = .pl_node,
-                .switch_cond_ref = .un_node,
-                .switch_capture = .switch_capture,
-                .switch_capture_ref = .switch_capture,
-                .switch_capture_multi = .switch_capture,
-                .switch_capture_multi_ref = .switch_capture,
-                .switch_capture_tag = .un_tok,
                 .array_base_ptr = .un_node,
                 .field_base_ptr = .un_node,
                 .validate_array_init_ty = .pl_node,
@@ -1716,12 +1676,12 @@ pub const Inst = struct {
                 .size_of = .un_node,
                 .bit_size_of = .un_node,
 
-                .ptr_to_int = .un_node,
+                .int_from_ptr = .un_node,
                 .compile_error = .un_node,
                 .set_eval_branch_quota = .un_node,
-                .enum_to_int = .un_node,
+                .int_from_enum = .un_node,
                 .align_of = .un_node,
-                .bool_to_int = .un_node,
+                .int_from_bool = .un_node,
                 .embed_file = .un_node,
                 .error_name = .un_node,
                 .panic = .un_node,
@@ -1746,10 +1706,10 @@ pub const Inst = struct {
                 .frame_type = .un_node,
                 .frame_size = .un_node,
 
-                .float_to_int = .pl_node,
+                .int_from_float = .pl_node,
-                .int_to_float = .pl_node,
+                .float_from_int = .pl_node,
-                .int_to_ptr = .pl_node,
+                .ptr_from_int = .pl_node,
-                .int_to_enum = .pl_node,
+                .enum_from_int = .pl_node,
                 .float_cast = .pl_node,
                 .int_cast = .pl_node,
                 .ptr_cast = .pl_node,
@@ -1945,16 +1905,6 @@ pub const Inst = struct {
         /// The `@prefetch` builtin.
         /// `operand` is payload index to `BinNode`.
         prefetch,
-        /// Given a pointer to a struct or object that contains virtual fields, returns the
-        /// named field.  If there is no named field, searches in the type for a decl that
-        /// matches the field name.  The decl is resolved and we ensure that it's a function
-        /// which can accept the object as the first parameter, with one pointer fixup.  If
-        /// all of that works, this instruction produces a special "bound function" value
-        /// which contains both the function and the saved first parameter value.
-        /// Bound functions may only be used as the function parameter to a `call` or
-        /// `builtin_call` instruction.  Any other use is invalid zir and may crash the compiler.
-        /// Uses `pl_node` field. The AST node is the `@field` builtin. Payload is FieldNamedNode.
-        field_call_bind_named,
         /// Implements the `@fence` builtin.
         /// `operand` is payload index to `UnNode`.
         fence,
@@ -1980,10 +1930,10 @@ pub const Inst = struct {
         select,
         /// Implement builtin `@errToInt`.
         /// `operand` is payload index to `UnNode`.
-        error_to_int,
+        int_from_error,
-        /// Implement builtin `@intToError`.
+        /// Implement builtin `@errorFromInt`.
         /// `operand` is payload index to `UnNode`.
-        int_to_error,
+        error_from_int,
         /// Implement builtin `@Type`.
         /// `operand` is payload index to `UnNode`.
         /// `small` contains `NameStrategy`.
@@ -2028,9 +1978,10 @@ pub const Inst = struct {
         /// Implements the `@inComptime` builtin.
         /// `operand` is `src_node: i32`.
         in_comptime,
-        /// Used as a placeholder for the capture of an `errdefer`.
+        /// Used as a placeholder instruction which is just a dummy index for Sema to replace
-        /// This is replaced by Sema with the captured value.
+        /// with a specific value. For instance, this is used for the capture of an `errdefer`.
-        errdefer_err_code,
+        /// This should never appear in a body.
+        value_placeholder,
 
         pub const InstData = struct {
             opcode: Extended,
@@ -2058,107 +2009,89 @@ pub const Inst = struct {
     /// The tag type is specified so that it is safe to bitcast between `[]u32`
     /// and `[]Ref`.
     pub const Ref = enum(u32) {
-        u1_type,
+        u1_type = @intFromEnum(InternPool.Index.u1_type),
-        u8_type,
+        u8_type = @intFromEnum(InternPool.Index.u8_type),
-        i8_type,
+        i8_type = @intFromEnum(InternPool.Index.i8_type),
-        u16_type,
+        u16_type = @intFromEnum(InternPool.Index.u16_type),
-        i16_type,
+        i16_type = @intFromEnum(InternPool.Index.i16_type),
-        u29_type,
+        u29_type = @intFromEnum(InternPool.Index.u29_type),
-        u32_type,
+        u32_type = @intFromEnum(InternPool.Index.u32_type),
-        i32_type,
+        i32_type = @intFromEnum(InternPool.Index.i32_type),
-        u64_type,
+        u64_type = @intFromEnum(InternPool.Index.u64_type),
-        i64_type,
+        i64_type = @intFromEnum(InternPool.Index.i64_type),
-        u128_type,
+        u128_type = @intFromEnum(InternPool.Index.u128_type),
-        i128_type,
+        i128_type = @intFromEnum(InternPool.Index.i128_type),
-        usize_type,
+        usize_type = @intFromEnum(InternPool.Index.usize_type),
-        isize_type,
+        isize_type = @intFromEnum(InternPool.Index.isize_type),
-        c_char_type,
+        c_char_type = @intFromEnum(InternPool.Index.c_char_type),
-        c_short_type,
+        c_short_type = @intFromEnum(InternPool.Index.c_short_type),
-        c_ushort_type,
+        c_ushort_type = @intFromEnum(InternPool.Index.c_ushort_type),
-        c_int_type,
+        c_int_type = @intFromEnum(InternPool.Index.c_int_type),
-        c_uint_type,
+        c_uint_type = @intFromEnum(InternPool.Index.c_uint_type),
-        c_long_type,
+        c_long_type = @intFromEnum(InternPool.Index.c_long_type),
-        c_ulong_type,
+        c_ulong_type = @intFromEnum(InternPool.Index.c_ulong_type),
-        c_longlong_type,
+        c_longlong_type = @intFromEnum(InternPool.Index.c_longlong_type),
-        c_ulonglong_type,
+        c_ulonglong_type = @intFromEnum(InternPool.Index.c_ulonglong_type),
-        c_longdouble_type,
+        c_longdouble_type = @intFromEnum(InternPool.Index.c_longdouble_type),
-        f16_type,
+        f16_type = @intFromEnum(InternPool.Index.f16_type),
-        f32_type,
+        f32_type = @intFromEnum(InternPool.Index.f32_type),
-        f64_type,
+        f64_type = @intFromEnum(InternPool.Index.f64_type),
-        f80_type,
+        f80_type = @intFromEnum(InternPool.Index.f80_type),
-        f128_type,
+        f128_type = @intFromEnum(InternPool.Index.f128_type),
-        anyopaque_type,
+        anyopaque_type = @intFromEnum(InternPool.Index.anyopaque_type),
-        bool_type,
+        bool_type = @intFromEnum(InternPool.Index.bool_type),
-        void_type,
+        void_type = @intFromEnum(InternPool.Index.void_type),
-        type_type,
+        type_type = @intFromEnum(InternPool.Index.type_type),
-        anyerror_type,
+        anyerror_type = @intFromEnum(InternPool.Index.anyerror_type),
-        comptime_int_type,
+        comptime_int_type = @intFromEnum(InternPool.Index.comptime_int_type),
-        comptime_float_type,
+        comptime_float_type = @intFromEnum(InternPool.Index.comptime_float_type),
-        noreturn_type,
+        noreturn_type = @intFromEnum(InternPool.Index.noreturn_type),
-        anyframe_type,
+        anyframe_type = @intFromEnum(InternPool.Index.anyframe_type),
-        empty_struct_literal,
+        empty_struct_type = @intFromEnum(InternPool.Index.empty_struct_type),
-        null_type,
+        null_type = @intFromEnum(InternPool.Index.null_type),
-        undefined_type,
+        undefined_type = @intFromEnum(InternPool.Index.undefined_type),
-        enum_literal_type,
+        enum_literal_type = @intFromEnum(InternPool.Index.enum_literal_type),
-        atomic_order_type,
+        atomic_order_type = @intFromEnum(InternPool.Index.atomic_order_type),
-        atomic_rmw_op_type,
+        atomic_rmw_op_type = @intFromEnum(InternPool.Index.atomic_rmw_op_type),
-        calling_convention_type,
+        calling_convention_type = @intFromEnum(InternPool.Index.calling_convention_type),
-        address_space_type,
+        address_space_type = @intFromEnum(InternPool.Index.address_space_type),
-        float_mode_type,
+        float_mode_type = @intFromEnum(InternPool.Index.float_mode_type),
-        reduce_op_type,
+        reduce_op_type = @intFromEnum(InternPool.Index.reduce_op_type),
-        modifier_type,
+        call_modifier_type = @intFromEnum(InternPool.Index.call_modifier_type),
-        prefetch_options_type,
+        prefetch_options_type = @intFromEnum(InternPool.Index.prefetch_options_type),
-        export_options_type,
+        export_options_type = @intFromEnum(InternPool.Index.export_options_type),
-        extern_options_type,
+        extern_options_type = @intFromEnum(InternPool.Index.extern_options_type),
-        type_info_type,
+        type_info_type = @intFromEnum(InternPool.Index.type_info_type),
-        manyptr_u8_type,
+        manyptr_u8_type = @intFromEnum(InternPool.Index.manyptr_u8_type),
-        manyptr_const_u8_type,
+        manyptr_const_u8_type = @intFromEnum(InternPool.Index.manyptr_const_u8_type),
-        fn_noreturn_no_args_type,
+        manyptr_const_u8_sentinel_0_type = @intFromEnum(InternPool.Index.manyptr_const_u8_sentinel_0_type),
-        fn_void_no_args_type,
+        single_const_pointer_to_comptime_int_type = @intFromEnum(InternPool.Index.single_const_pointer_to_comptime_int_type),
-        fn_naked_noreturn_no_args_type,
+        slice_const_u8_type = @intFromEnum(InternPool.Index.slice_const_u8_type),
-        fn_ccc_void_no_args_type,
+        slice_const_u8_sentinel_0_type = @intFromEnum(InternPool.Index.slice_const_u8_sentinel_0_type),
-        single_const_pointer_to_comptime_int_type,
+        optional_noreturn_type = @intFromEnum(InternPool.Index.optional_noreturn_type),
-        const_slice_u8_type,
+        anyerror_void_error_union_type = @intFromEnum(InternPool.Index.anyerror_void_error_union_type),
-        anyerror_void_error_union_type,
+        generic_poison_type = @intFromEnum(InternPool.Index.generic_poison_type),
-        generic_poison_type,
+        unknown_type = @intFromEnum(InternPool.Index.unknown_type),
-        unknown_type,
 
-        /// `undefined` (untyped)
+        undef = @intFromEnum(InternPool.Index.undefined_value),
-        undef,
+        zero = @intFromEnum(InternPool.Index.zero_comptime_int),
-        /// `0` (comptime_int)
+        zero_u8 = @intFromEnum(InternPool.Index.zero_u8),
-        zero,
+        one = @intFromEnum(InternPool.Index.one_comptime_int),
-        /// `1` (comptime_int)
+        one_u8 = @intFromEnum(InternPool.Index.one_u8),
-        one,
+        void_value = @intFromEnum(InternPool.Index.void_value),
-        /// `{}`
+        unreachable_value = @intFromEnum(InternPool.Index.unreachable_value),
-        void_value,
+        null_value = @intFromEnum(InternPool.Index.null_value),
-        /// `unreachable` (noreturn type)
+        bool_true = @intFromEnum(InternPool.Index.bool_true),
-        unreachable_value,
+        bool_false = @intFromEnum(InternPool.Index.bool_false),
-        /// `null` (untyped)
+        empty_aggregate = @intFromEnum(InternPool.Index.empty_aggregate),
-        null_value,
+        zero_usize = @intFromEnum(InternPool.Index.zero_usize),
-        /// `true`
+        one_usize = @intFromEnum(InternPool.Index.one_usize),
-        bool_true,
+        the_only_possible_value = @intFromEnum(InternPool.Index.the_only_possible_value),
-        /// `false`
+        generic_poison = @intFromEnum(InternPool.Index.generic_poison),
-        bool_false,
+        unknown_unknown = @intFromEnum(InternPool.Index.unknown_unknown),
-        /// `.{}` (untyped)
-        empty_struct,
-        /// `0` (usize)
-        zero_usize,
-        /// `1` (usize)
-        one_usize,
-        /// `std.builtin.CallingConvention.C`
-        calling_convention_c,
-        /// `std.builtin.CallingConvention.Inline`
-        calling_convention_inline,
-        /// Used for generic parameters where the type and value
-        /// is not known until generic function instantiation.
-        generic_poison,
-        unknown,
 
         ref_start_index,
-
+        none = @intFromEnum(InternPool.Index.none),
-        /// This Ref does not correspond to any ZIR instruction or constant
-        /// value and may instead be used as a sentinel to indicate null.
-        none = std.math.maxInt(u32),
         _,
     };
 
@@ -2290,10 +2223,6 @@ pub const Inst = struct {
             operand: Ref,
             payload_index: u32,
         },
-        switch_capture: struct {
-            switch_inst: Index,
-            prong_index: u32,
-        },
         dbg_stmt: LineColumn,
         /// Used for unary operators which reference an inst,
         /// with an AST node source location.
@@ -2363,7 +2292,6 @@ pub const Inst = struct {
             bool_br,
             @"unreachable",
             @"break",
-            switch_capture,
             dbg_stmt,
             inst_node,
             str_op,
@@ -2579,6 +2507,19 @@ pub const Inst = struct {
         };
     };
 
+    /// Stored inside extra, with trailing arguments according to `args_len`.
+    /// Implicit 0. arg_0_start: u32, // always same as `args_len`
+    /// 1. arg_end: u32, // for each `args_len`
+    /// arg_N_start is the same as arg_N-1_end
+    pub const FieldCall = struct {
+        // Note: Flags *must* come first so that unusedResultExpr
+        // can find it when it goes to modify them.
+        flags: Call.Flags,
+        obj_ptr: Ref,
+        /// Offset into `string_bytes`.
+        field_name_start: u32,
+    };
+
     pub const TypeOfPeer = struct {
         src_node: i32,
         body_len: u32,
@@ -2658,6 +2599,14 @@ pub const Inst = struct {
         sentinel: Ref,
     };
 
+    pub const SliceLength = struct {
+        lhs: Ref,
+        start: Ref,
+        len: Ref,
+        sentinel: Ref,
+        start_src_node_offset: i32,
+    };
+
     /// The meaning of these operands depends on the corresponding `Tag`.
     pub const Bin = struct {
         lhs: Ref,
@@ -2681,37 +2630,53 @@ pub const Inst = struct {
     };
 
     /// 0. multi_cases_len: u32 // If has_multi_cases is set.
-    /// 1. else_body { // If has_else or has_under is set.
+    /// 1. tag_capture_inst: u32 // If any_has_tag_capture is set. Index of instruction prongs use to refer to the inline tag capture.
-    ///        body_len: u32,
+    /// 2. else_body { // If has_else or has_under is set.
-    ///        body member Index for every body_len
+    ///        info: ProngInfo,
+    ///        body member Index for every info.body_len
     ///     }
-    /// 2. scalar_cases: { // for every scalar_cases_len
+    /// 3. scalar_cases: { // for every scalar_cases_len
     ///        item: Ref,
-    ///        body_len: u32,
+    ///        info: ProngInfo,
-    ///        body member Index for every body_len
+    ///        body member Index for every info.body_len
     ///     }
-    /// 3. multi_cases: { // for every multi_cases_len
+    /// 4. multi_cases: { // for every multi_cases_len
     ///        items_len: u32,
     ///        ranges_len: u32,
-    ///        body_len: u32,
+    ///        info: ProngInfo,
     ///        item: Ref // for every items_len
     ///        ranges: { // for every ranges_len
     ///            item_first: Ref,
     ///            item_last: Ref,
     ///        }
-    ///        body member Index for every body_len
+    ///        body member Index for every info.body_len
     ///    }
+    ///
+    /// When analyzing a case body, the switch instruction itself refers to the
+    /// captured payload. Whether this is captured by reference or by value
+    /// depends on whether the `byref` bit is set for the corresponding body.
     pub const SwitchBlock = struct {
-        /// This is always a `switch_cond` or `switch_cond_ref` instruction.
+        /// The operand passed to the `switch` expression. If this is a
-        /// If it is a `switch_cond_ref` instruction, bits.is_ref is always true.
+        /// `switch_block`, this is the operand value; if `switch_block_ref` it
-        /// If it is a `switch_cond` instruction, bits.is_ref is always false.
+        /// is a pointer to the operand. `switch_block_ref` is always used if
-        /// Both `switch_cond` and `switch_cond_ref` return a value, not a pointer,
+        /// any prong has a byref capture.
-        /// that is useful for the case items, but cannot be used for capture values.
-        /// For the capture values, Sema is expected to find the operand of this operand
-        /// and use that.
         operand: Ref,
         bits: Bits,
 
+        /// These are stored in trailing data in `extra` for each prong.
+        pub const ProngInfo = packed struct(u32) {
+            body_len: u28,
+            capture: Capture,
+            is_inline: bool,
+            has_tag_capture: bool,
+
+            pub const Capture = enum(u2) {
+                none,
+                by_val,
+                by_ref,
+            };
+        };
+
         pub const Bits = packed struct {
             /// If true, one or more prongs have multiple items.
             has_multi_cases: bool,
@@ -2719,9 +2684,11 @@ pub const Inst = struct {
             has_else: bool,
             /// If true, there is an underscore prong. This is mutually exclusive with `has_else`.
             has_under: bool,
+            /// If true, at least one prong has an inline tag capture.
+            any_has_tag_capture: bool,
             scalar_cases_len: ScalarCasesLen,
 
-            pub const ScalarCasesLen = u29;
+            pub const ScalarCasesLen = u28;
 
             pub fn specialProng(bits: Bits) SpecialProng {
                 const has_else: u2 = @intFromBool(bits.has_else);
@@ -2735,103 +2702,10 @@ pub const Inst = struct {
             }
         };
 
-        pub const ScalarProng = struct {
-            item: Ref,
-            body: []const Index,
-        };
-
-        /// TODO performance optimization: instead of having this helper method
-        /// change the definition of switch_capture instruction to store extra_index
-        /// instead of prong_index. This way, Sema won't be doing O(N^2) iterations
-        /// over the switch prongs.
-        pub fn getScalarProng(
-            self: SwitchBlock,
-            zir: Zir,
-            extra_end: usize,
-            prong_index: usize,
-        ) ScalarProng {
-            var extra_index: usize = extra_end;
-
-            if (self.bits.has_multi_cases) {
-                extra_index += 1;
-            }
-
-            if (self.bits.specialProng() != .none) {
-                const body_len = @truncate(u31, zir.extra[extra_index]);
-                extra_index += 1;
-                const body = zir.extra[extra_index..][0..body_len];
-                extra_index += body.len;
-            }
-
-            var scalar_i: usize = 0;
-            while (true) : (scalar_i += 1) {
-                const item = @enumFromInt(Ref, zir.extra[extra_index]);
-                extra_index += 1;
-                const body_len = @truncate(u31, zir.extra[extra_index]);
-                extra_index += 1;
-                const body = zir.extra[extra_index..][0..body_len];
-                extra_index += body.len;
-
-                if (scalar_i < prong_index) continue;
-
-                return .{
-                    .item = item,
-                    .body = body,
-                };
-            }
-        }
-
         pub const MultiProng = struct {
             items: []const Ref,
             body: []const Index,
         };
-
-        pub fn getMultiProng(
-            self: SwitchBlock,
-            zir: Zir,
-            extra_end: usize,
-            prong_index: usize,
-        ) MultiProng {
-            // +1 for self.bits.has_multi_cases == true
-            var extra_index: usize = extra_end + 1;
-
-            if (self.bits.specialProng() != .none) {
-                const body_len = @truncate(u31, zir.extra[extra_index]);
-                extra_index += 1;
-                const body = zir.extra[extra_index..][0..body_len];
-                extra_index += body.len;
-            }
-
-            var scalar_i: usize = 0;
-            while (scalar_i < self.bits.scalar_cases_len) : (scalar_i += 1) {
-                extra_index += 1;
-                const body_len = @truncate(u31, zir.extra[extra_index]);
-                extra_index += 1;
-                extra_index += body_len;
-            }
-            var multi_i: u32 = 0;
-            while (true) : (multi_i += 1) {
-                const items_len = zir.extra[extra_index];
-                extra_index += 1;
-                const ranges_len = zir.extra[extra_index];
-                extra_index += 1;
-                const body_len = @truncate(u31, zir.extra[extra_index]);
-                extra_index += 1;
-                const items = zir.refSlice(extra_index, items_len);
-                extra_index += items_len;
-                // Each range has a start and an end.
-                extra_index += 2 * ranges_len;
-
-                const body = zir.extra[extra_index..][0..body_len];
-                extra_index += body_len;
-
-                if (multi_i < prong_index) continue;
-                return .{
-                    .items = items,
-                    .body = body,
-                };
-            }
-        }
     };
 
     pub const Field = struct {
@@ -2845,12 +2719,6 @@ pub const Inst = struct {
         field_name: Ref,
     };
 
-    pub const FieldNamedNode = struct {
-        node: i32,
-        lhs: Ref,
-        field_name: Ref,
-    };
-
     pub const As = struct {
         dest_type: Ref,
         operand: Ref,
@@ -3832,6 +3700,7 @@ pub fn indexToRef(inst: Inst.Index) Inst.Ref {
 }
 
 pub fn refToIndex(inst: Inst.Ref) ?Inst.Index {
+    assert(inst != .none);
     const ref_int = @intFromEnum(inst);
     if (ref_int >= ref_start_index) {
         return ref_int - ref_start_index;
@@ -3839,3 +3708,8 @@ pub fn refToIndex(inst: Inst.Ref) ?Inst.Index {
         return null;
     }
 }
+
+pub fn refToIndexAllowNone(inst: Inst.Ref) ?Inst.Index {
+    if (inst == .none) return null;
+    return refToIndex(inst);
+}

src/translate_c.zig

@@ -236,12 +236,10 @@ pub fn translate(
                 const body_size = @sizeOf(std.zig.Server.Message.EmitBinPath);
                 if (header.bytes_len <= body_size) return error.InvalidResponse;
 
-                const trailing_size = header.bytes_len - body_size;
-
                 _ = try zcs.receiveEmitBinPath();
 
-                const result_path = try zcs.receiveBytes(allocator, trailing_size);
+                const trailing_size = header.bytes_len - body_size;
-                defer allocator.free(result_path);
+                const result_path = zcs.pooler.fifo(.in).readableSliceOfLen(trailing_size);
 
                 return Result{ .success = try URI.fromPath(allocator, std.mem.sliceTo(result_path, '\n')) };
             },

tests/lsp_features/completion.zig

@@ -509,6 +509,17 @@ test "completion - block" {
     , &.{
         .{ .label = "blk", .kind = .Text }, // idk what kind this should be
     });
+
+    try testCompletion(
+        \\const S = struct { alpha: u32 };
+        \\const foo: S = undefined;
+        \\const bar = blk: {
+        \\    break :blk foo;
+        \\};
+        \\const baz = bar.<cursor>
+    , &.{
+        .{ .label = "alpha", .kind = .Field, .detail = "alpha: u32" },
+    });
 }
 
 fn testCompletion(source: []const u8, expected_completions: []const Completion) !void {

tests/lsp_features/inlay_hints.zig

@@ -48,6 +48,23 @@ test "inlayhints - function self parameter" {
         \\const foo: Foo = .{};
         \\const _ = foo.bar(<alpha>5,<beta>"");
     );
+    try testInlayHints(
+        \\const Foo = struct { pub fn bar(self: Foo, alpha: u32, beta: anytype) void {} };
+        \\const foo: Foo = .{};
+        \\const _ = foo.bar(<alpha>5,<beta>4);
+    );
+    try testInlayHints(
+        \\const Foo = struct { pub fn bar(self: Foo, alpha: u32, beta: []const u8) void {} };
+        \\const _ = Foo.bar(<self>undefined,<alpha>5,<beta>"");
+    );
+    try testInlayHints(
+        \\const Foo = struct {
+        \\  pub fn bar(self: Foo, alpha: u32, beta: []const u8) void {}
+        \\  pub fn foo() void {
+        \\      bar(<self>undefined,<alpha>5,<beta>"");
+        \\  }
+        \\};
+    );
 }
 
 test "inlayhints - builtin call" {