Added switch to declFromIndex, fixed occasional crash

src/analysis.zig

@@ -610,6 +610,19 @@ pub fn declsFromIndexInternal(decls: *std.ArrayList(*ast.Node), tree: *ast.Tree,
                 }
             }
         },
+        .Switch => {
+            const switch_node = node.cast(ast.Node.Switch).?;
+            var case_it = switch_node.cases.iterator(0);
+            while (case_it.next()) |case| {
+                const case_node = case.*.cast(ast.Node.SwitchCase).?;
+                if (nodeContainsSourceIndex(tree, case_node.expr, source_index)) {
+                    if (case_node.payload) |payload| {
+                        try declsFromIndexInternal(decls, tree, payload, source_index);
+                    }
+                    return try declsFromIndexInternal(decls, tree, case_node.expr, source_index);
+                }
+            }
+        },
         // TODO: These convey no type information...
         .Payload => try decls.append(node.cast(ast.Node.Payload).?.error_symbol),
         .PointerPayload => try decls.append(node.cast(ast.Node.PointerPayload).?.value_symbol),

src/main.zig

@@ -293,10 +293,11 @@ fn identifierFromPosition(pos_index: usize, handle: DocumentStore.Handle) []cons
     {}
 
     var end_idx = pos_index;
-    while (end_idx < handle.document.text.len - 1 and
+    while (end_idx < handle.document.text.len and
         (std.ascii.isAlNum(text[end_idx]) or text[end_idx] == '_')) : (end_idx += 1)
     {}
 
+    if (end_idx <= start_idx) return &[0]u8{};
     return text[start_idx + 1 .. end_idx];
 }