diff --git a/src/compiler.c b/src/compiler.c
index fb989b4..ed8f4e5 100644
--- a/src/compiler.c
+++ b/src/compiler.c
@@ -472,6 +472,16 @@ claimCreate (const System sys, const Protocol protocol, const Role role,
 	      /* then we should ignore it later */
 	      cl->alwaystrue = true;
 	      cl->warnings = true;
+
+	      /* show a warning for this */
+	      globalError++;
+	      eprintf ("warning: secrecy claim of role ");
+	      termPrint (cl->rolename);
+	      eprintf (" contains a variable ");
+	      termPrint (claimvars->term);
+	      eprintf
+		(" which is never read; therefore the claim will be true.\n");
+	      globalError--;
 	    }
 	  claimvars = claimvars->next;
 	}
@@ -1579,11 +1589,19 @@ compute_prec_sets (const System sys)
       //@todo This is for debugging, mainly.
       if (cl->prec == NULL)
 	{
-	  globalError++;
-	  eprintf ("warning: claim with empty prec() set at r:%i, ev:%i\n",
-		   r1, ev1);
-	  globalError--;
-	  cl->warnings = true;
+	  if (inTermlist (CLAIMS_dep_prec, cl->type))
+	    {
+	      /* this claim depends on prec, but it is empty! */
+
+	      cl->warnings = true;
+	      globalError++;
+	      eprintf ("warning: claim with label ");
+	      termPrint (cl->label);
+	      eprintf (" of role ");
+	      termPrint (cl->rolename);
+	      eprintf (" has an empty prec() set.\n");
+	      globalError--;
+	    }
 	}
       else
 	{
diff --git a/src/specialterm.c b/src/specialterm.c
index aa16b14..1607701 100644
--- a/src/specialterm.c
+++ b/src/specialterm.c
@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include "term.h"
+#include "termlist.h"
 #include "compiler.h"
 
 /*
@@ -28,6 +29,8 @@ Term CLAIM_Niagree;
 Term CLAIM_Empty;
 Term CLAIM_Reachable;
 
+Termlist CLAIMS_dep_prec;
+
 //! Init special terms
 /**
  * This is called by compilerInit
@@ -52,4 +55,10 @@ specialTermInit (const System sys)
   langcons (CLAIM_Niagree, "Niagree", TERM_Claim);
   langcons (CLAIM_Empty, "Empty", TERM_Claim);
   langcons (CLAIM_Reachable, "Reachable", TERM_Claim);
+
+  /* Construct a list of claims that depend on prec being not-empty */
+  /* basically all authentication claims */
+  CLAIMS_dep_prec = termlistAdd (NULL, CLAIM_Niagree);
+  CLAIMS_dep_prec = termlistAdd (CLAIMS_dep_prec, CLAIM_Nisynch);
+
 }
diff --git a/src/specialterm.h b/src/specialterm.h
index de0f9b3..5e877ad 100644
--- a/src/specialterm.h
+++ b/src/specialterm.h
@@ -1,6 +1,9 @@
 #ifndef SPECIALTERM
 #define SPECIALTERM
 
+#include "term.h"
+#include "termlist.h"
+
 /*
  * Some declarations in spercialterm.c
  */
@@ -20,4 +23,6 @@ extern Term CLAIM_Niagree;
 extern Term CLAIM_Empty;
 extern Term CLAIM_Reachable;
 
+extern Termlist CLAIMS_dep_prec;
+
 #endif