Fix Issue 18620 - error cannot be interpreted at compile time is miss…

…ing context where error ocurrs

src/dmd/ctfeexpr.d

@@ -200,14 +200,15 @@ extern (C++) final class ThrownExceptionExp : Expression
     }
 }
 
+
 /***********************************************************
  * This type is only used by the interpreter.
  */
-extern (C++) final class CTFEExp : Expression
+extern (C++) class CTFEExp : Expression
 {
-    extern (D) this(TOK tok)
+    extern (D) this(TOK tok, int size = __traits(classInstanceSize, CTFEExp))
     {
-        super(Loc.initial, tok, __traits(classInstanceSize, CTFEExp));
+        super(Loc.initial, tok, size);
         type = Type.tvoid;
     }
 
@@ -247,6 +248,30 @@ extern (C++) final class CTFEExp : Expression
     }
 }
 
+enum CTE : int
+{
+    missingFuncBody,
+}
+
+/* This class is used to pass CTFE errors to
+ * higher levels in the AST so that error
+ * messages can be written on the call site
+ */
+extern (C++) final class CTErrorExp : CTFEExp
+{
+    CTE err;
+    extern (D) this(CTE err)
+    {
+        super(TOK.cantExpression, __traits(classInstanceSize, CTErrorExp));
+        this.err = err;
+    }
+
+    override inout(CTErrorExp) isCTErrorExp() inout
+    {
+        return this;
+    }
+}
+
 // True if 'e' is CTFEExp::cantexp, or an exception
 extern (C++) bool exceptionOrCantInterpret(const Expression e)
 {

src/dmd/dinterpret.d

@@ -4997,7 +4997,7 @@ public:
         if (!fd.fbody)
         {
             e.error("`%s` cannot be interpreted at compile time, because it has no available source code", fd.toChars());
-            result = CTFEExp.cantexp;
+            result = new CTErrorExp(CTE.missingFuncBody);
             return;
         }
 

src/dmd/dsymbolsem.d

@@ -22,6 +22,7 @@ import dmd.astcodegen;
 import dmd.attrib;
 import dmd.blockexit;
 import dmd.clone;
+import dmd.ctfeexpr;
 import dmd.dcast;
 import dmd.dclass;
 import dmd.declaration;
@@ -560,10 +561,10 @@ private extern(C++) final class DsymbolSemanticVisitor : Visitor
     {
         version (none)
         {
-            printf("VarDeclaration::semantic('%s', parent = '%s') sem = %d\n", toChars(), sc.parent ? sc.parent.toChars() : null, sem);
-            printf(" type = %s\n", type ? type.toChars() : "null");
+            printf("VarDeclaration::semantic('%s', parent = '%s')\n", dsym.toChars(), sc.parent ? sc.parent.toChars() : null);
+            printf(" type = %s\n", dsym.type ? dsym.type.toChars() : "null");
             printf(" stc = x%x\n", sc.stc);
-            printf(" storage_class = x%llx\n", storage_class);
+            printf(" storage_class = x%llx\n", dsym.storage_class);
             printf("linkage = %d\n", sc.linkage);
             //if (strcmp(toChars(), "mul") == 0) assert(0);
         }
@@ -1139,7 +1140,7 @@ private extern(C++) final class DsymbolSemanticVisitor : Visitor
                 // possibilities.
                 if (fd && !(dsym.storage_class & (STC.manifest | STC.static_ | STC.tls | STC.gshared | STC.extern_)) && !dsym._init.isVoidInitializer())
                 {
-                    //printf("fd = '%s', var = '%s'\n", fd.toChars(), toChars());
+                    //printf("fd = '%s', var = '%s'\n", fd.toChars(), dsym.toChars());
                     if (!ei)
                     {
                         ArrayInitializer ai = dsym._init.isArrayInitializer();
@@ -1215,9 +1216,23 @@ private extern(C++) final class DsymbolSemanticVisitor : Visitor
                 }
                 else
                 {
+                    import dmd.hdrgen : toCBuffer, HdrGenState;
+                    OutBuffer buff;
+                    HdrGenState hgs;
+                    toCBuffer(dsym, &buff, &hgs);
+                    if (buff.offset != 0)
+                        buff.setsize(buff.offset-1);
+
                     // https://issues.dlang.org/show_bug.cgi?id=14166
                     // Don't run CTFE for the temporary variables inside typeof
                     dsym._init = dsym._init.initializerSemantic(sc, dsym.type, sc.intypeof == 1 ? INITnointerpret : INITinterpret);
+                    const init_err = dsym._init.isExpInitializer();
+                    if (init_err)
+                    {
+                        const errExp = init_err.exp.isCTErrorExp;
+                        if (errExp && errExp.err == CTE.missingFuncBody)
+                            errorSupplemental(dsym.loc, "compile time context created here: `%s`", buff.extractString());
+                    }
                 }
             }
             else if (parent.isAggregateDeclaration())

src/dmd/expression.d

@@ -2546,6 +2546,11 @@ extern (C++) abstract class Expression : RootObject
         return false;
     }
 
+    inout(CTErrorExp) isCTErrorExp() inout
+    {
+        return null;
+    }
+
     final Expression op_overload(Scope* sc)
     {
         return .op_overload(this, sc);

src/dmd/initsem.d

@@ -394,7 +394,7 @@ private extern(C++) final class InitializerSemanticVisitor : Visitor
 
     override void visit(ExpInitializer i)
     {
-        //printf("ExpInitializer::semantic(%s), type = %s\n", exp.toChars(), t.toChars());
+        //printf("ExpInitializer::semantic(%s), type = %s\n", i.exp.toChars(), t.toChars());
         if (needInterpret)
             sc = sc.startCTFE();
         i.exp = i.exp.expressionSemantic(sc);
@@ -546,7 +546,7 @@ private extern(C++) final class InitializerSemanticVisitor : Visitor
             i.exp = i.exp.ctfeInterpret();
         else
             i.exp = i.exp.optimize(WANTvalue);
-        //printf("-ExpInitializer::semantic(): "); exp.print();
+        //printf("-ExpInitializer::semantic(): "); i.exp.print();
         result = i;
     }
 }
@@ -895,7 +895,7 @@ private extern(C++) final class InitToExpressionVisitor : Visitor
     {
         if (itype)
         {
-            //printf("ExpInitializer::toExpression(t = %s) exp = %s\n", t.toChars(), exp.toChars());
+            //printf("ExpInitializer::toExpression(t = %s) exp = %s\n", itype.toChars(), i.exp.toChars());
             Type tb = itype.toBasetype();
             Expression e = (i.exp.op == TOK.construct || i.exp.op == TOK.blit) ? (cast(AssignExp)i.exp).e2 : i.exp;
             if (tb.ty == Tsarray && e.implicitConvTo(tb.nextOf()))

test/fail_compilation/fail18620.d

@@ -0,0 +1,21 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/fail18620.d(14): Error: `strlen` cannot be interpreted at compile time, because it has no available source code
+fail_compilation/fail18620.d(19):        compile time context created here: `static A a = new A("a");`
+fail_compilation/fail18620.d(14): Error: `strlen` cannot be interpreted at compile time, because it has no available source code
+fail_compilation/fail18620.d(20):        compile time context created here: `__gshared A b = new A("b");`
+---
+*/
+class A{
+    this(const(char)* s)
+    {
+        import core.stdc.string;
+        auto a=strlen(s);
+    }
+}
+
+void main(){
+    static a = new A("a");
+    __gshared b = new A("b");
+}