Fix Issue 22054 - Referencing a fwd-declared field results in many er…

…ror messages
dlang · Jul 5, 2021 · ef3ff05 · ef3ff05
1 parent 8423098
commit ef3ff05
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Showing 3 changed files with 26 additions and 2 deletions.
diff --git a/src/dmd/dclass.d b/src/dmd/dclass.d
@@ -498,7 +498,7 @@ extern (C++) class ClassDeclaration : AggregateDeclaration
         if (!members || !symtab) // opaque or addMember is not yet done
         {
             // .stringof is always defined (but may be hidden by some other symbol)
-            if (ident != Id.stringof && !(flags & IgnoreErrors))
+            if (ident != Id.stringof && !(flags & IgnoreErrors) && semanticRun < PASS.semanticdone)
                 error("is forward referenced when looking for `%s`", ident.toChars());
             //*(char*)0=0;
             return null;

diff --git a/src/dmd/typesem.d b/src/dmd/typesem.d
@@ -2387,8 +2387,12 @@ Expression getProperty(Type t, Scope* scope_, const ref Loc loc, Identifier iden
                     error(loc, "no property `%s` for type `%s`", ident.toChars(), mt.toPrettyChars(true));
                     if (auto dsym = mt.toDsymbol(scope_))
                         if (auto sym = dsym.isAggregateDeclaration())
+                        {
                             if (auto fd = search_function(sym, Id.opDispatch))
                                 errorSupplemental(loc, "potentially malformed `opDispatch`. Use an explicit instantiation to get a better error message");
+                            else if (!sym.members)
+                                errorSupplemental(loc, "`%s` `%s` is forward declared and does not have a body.", sym.kind, mt.toPrettyChars(true));
+                        }
                 }
             }
             e = ErrorExp.get();
@@ -3730,7 +3734,11 @@ Expression dotExp(Type mt, Scope* sc, Expression e, Identifier ident, int flag)
         assert(mt.ty == Tstruct || mt.ty == Tclass);
         auto sym = mt.toDsymbol(sc).isAggregateDeclaration();
         assert(sym);
-        if (ident != Id.__sizeof &&
+        if (// https://issues.dlang.org/show_bug.cgi?id=22054
+            // if a class or struct does not have a body
+            // there is no point in searching for its members
+            sym.members &&
+            ident != Id.__sizeof &&
             ident != Id.__xalignof &&
             ident != Id._init &&
             ident != Id._mangleof &&

diff --git a/test/fail_compilation/fail22054.d b/test/fail_compilation/fail22054.d
@@ -0,0 +1,16 @@
+// https://issues.dlang.org/show_bug.cgi?id=22054
+
+/*
+TEST_OUTPUT:
+---
+fail_compilation/test22054.d(15): Error: no property `what` for type `test22054.exception`
+fail_compilation/test22054.d(15):        `class` `test22054.exception` is forward declared and does not have a body.
+---
+*/
+
+class exception;
+
+void main ()
+{
+    assert(exception.what() == "Hello");
+}