Issue 15172 - ICE(interpret.c ctfeCompile) Assertion `!fd->semantic3E…

…rrors' failed.

src/func.c

@@ -2141,10 +2141,15 @@ void FuncDeclaration::semantic3(Scope *sc)
     //fflush(stdout);
 }
 
+/****************************************************
+ * Resolve forward reference of function signature -
+ * parameter types, return type, and attributes.
+ * Returns false if any errors exist in the signature.
+ */
 bool FuncDeclaration::functionSemantic()
 {
     if (!_scope)
-        return true;
+        return !errors;
 
     if (!originalType)      // semantic not yet run
     {
@@ -2162,6 +2167,9 @@ bool FuncDeclaration::functionSemantic()
     }
 
     // if inferring return type, sematic3 needs to be run
+    // - When the function body contains any errors, we cannot assume
+    //   the inferred return type is valid.
+    //   So, the body errors should become the function signature error.
     if (inferRetType && type && !type->nextOf())
         return functionSemantic3();
 
@@ -2179,15 +2187,19 @@ bool FuncDeclaration::functionSemantic()
             //ad->sizeok = SIZEOKfwd;
         }
         else
-            return functionSemantic3();
+            return functionSemantic3() || !errors;
     }
 
     if (storage_class & STCinference)
-        return functionSemantic3();
+        return functionSemantic3() || !errors;
 
-    return true;
+    return !errors;
 }
 
+/****************************************************
+ * Resolve forward reference of function body.
+ * Returns false if any errors exist in the body.
+ */
 bool FuncDeclaration::functionSemantic3()
 {
     if (semanticRun < PASSsemantic3 && _scope)
@@ -2212,7 +2224,7 @@ bool FuncDeclaration::functionSemantic3()
             return false;
     }
 
-    return true;
+    return !errors && !semantic3Errors;
 }
 
 VarDeclaration *FuncDeclaration::declareThis(Scope *sc, AggregateDeclaration *ad)

src/interpret.c

@@ -720,9 +720,13 @@ void ctfeCompile(FuncDeclaration *fd)
 }
 
 /*************************************
- *
  * Entry point for CTFE.
- * A compile-time result is required. Give an error if not possible
+ * A compile-time result is required. Give an error if not possible.
+ *
+ * `e` must be semantically valid expression. In other words, it should not
+ * contain any `ErrorExp`s in it. But, CTFE interpretation will cross over
+ * functions and may invoke a function that contains `ErrorStatement` in its body.
+ * If that, the "CTFE failed because of previous errors" error is raised.
  */
 Expression *ctfeInterpret(Expression *e)
 {
@@ -733,8 +737,6 @@ Expression *ctfeInterpret(Expression *e)
     if (e->type->ty == Terror)
         return new ErrorExp();
 
-    unsigned olderrors = global.errors;
-
     // This code is outside a function, but still needs to be compiled
     // (there are compiler-generated temporary variables such as __dollar).
     // However, this will only be run once and can then be discarded.
@@ -746,10 +748,7 @@ Expression *ctfeInterpret(Expression *e)
     if (!CTFEExp::isCantExp(result))
         result = scrubReturnValue(e->loc, result);
     if (CTFEExp::isCantExp(result))
-    {
-        assert(global.errors != olderrors);
         result = new ErrorExp();
-    }
     return result;
 }
 

src/template.c

@@ -2422,7 +2422,12 @@ void functionResolve(Match *m, Dsymbol *dstart, Loc loc, Scope *sc,
                 return 0;
 
             if (fd->type->ty != Tfunction)
-                goto Lerror;
+            {
+                m->lastf = fd;   // to propagate "error match"
+                m->count = 1;
+                m->last = MATCHnomatch;
+                return 1;
+            }
 
             Type *tthis_fd = fd->needThis() && !fd->isCtorDeclaration() ? tthis : NULL;