Add method-specific diagnostics

to diagnose virtual function failures

Author: snarang181

clang/lib/Sema/SemaTypeTraits.cpp

@@ -2345,6 +2345,13 @@ static void DiagnoseNonStandardLayoutReason(Sema &SemaRef, SourceLocation Loc,
   if (D->isPolymorphic()) {
     SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
         << diag::TraitNotSatisfiedReason::VirtualFunction;
+
+    for (const CXXMethodDecl *Method : D->methods()) {
+      if (Method->isVirtual()) {
+        SemaRef.Diag(Method->getLocation(), diag::note_defined_here) << Method;
+        break;
+      }
+    }
   }
   for (const FieldDecl *Field : D->fields()) {
     if (!Field->getType()->isStandardLayoutType()) {

clang/test/SemaCXX/type-traits-unsatisfied-diags.cpp

@@ -491,12 +491,13 @@ static_assert(__is_trivially_copyable(S12));
 
 namespace standard_layout_tests {
 struct WithVirtual { // #sl-Virtual
-    virtual void foo();
+    virtual void foo(); // #sl-Virtual-Foo
 };
 static_assert(__is_standard_layout(WithVirtual));
 // expected-error@-1 {{static assertion failed due to requirement '__is_standard_layout(standard_layout_tests::WithVirtual)'}} \
 // expected-note@-1 {{'WithVirtual' is not standard-layout}} \
 // expected-note@-1 {{because it has a virtual function}} \
+// expected-note@#sl-Virtual-Foo {{'foo' defined here}} \
 // expected-note@#sl-Virtual {{'WithVirtual' defined here}}
 
 struct MixedAccess { // #sl-Mixed
@@ -520,6 +521,7 @@ static_assert(__is_standard_layout(VB));
 // expected-note@-1 {{because it has a non-standard-layout base 'VirtualBase'}} \
 // expected-note@-1 {{because it has a virtual function}}
 // expected-note@#sl-VB {{'VB' defined here}}
+// expected-note@#sl-VB {{'~VB' defined here}}
 
 union U {      // #sl-U
 public: