We may fail to map a declaration in a template to its instantiated
declaration because of interesting ordering dependencies while
instantiating a class template or member class thereof. Complain,
rather than asserting (+Asserts) or silently rejecting the code
(-Asserts).
Fixes the crash-on-invalid in PR8965.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127129 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 0b46642..102ef51 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3001,11 +3001,14 @@
// If our context used to be dependent, we may need to instantiate
// it before performing lookup into that context.
+ bool IsBeingInstantiated = false;
if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
if (!Spec->isDependentContext()) {
QualType T = Context.getTypeDeclType(Spec);
const RecordType *Tag = T->getAs<RecordType>();
assert(Tag && "type of non-dependent record is not a RecordType");
+ if (Tag->isBeingDefined())
+ IsBeingInstantiated = true;
if (!Tag->isBeingDefined() &&
RequireCompleteType(Loc, T, diag::err_incomplete_type))
return 0;
@@ -3032,13 +3035,29 @@
ParentDC->decls_end());
}
- // UsingShadowDecls can instantiate to nothing because of using hiding.
- // Note: this assertion end up firing in invalid code even when none of the
- // AST invariants have been broken, so we explicitly check whether any
- // errors have been emitted
- assert((Result || isa<UsingShadowDecl>(D) || Diags.hasErrorOccurred()) &&
- "Unable to find instantiation of declaration!");
-
+ if (!Result) {
+ if (isa<UsingShadowDecl>(D)) {
+ // UsingShadowDecls can instantiate to nothing because of using hiding.
+ } else if (Diags.hasErrorOccurred()) {
+ // We've already complained about something, so most likely this
+ // declaration failed to instantiate. There's no point in complaining
+ // further, since this is normal in invalid code.
+ } else if (IsBeingInstantiated) {
+ // The class in which this member exists is currently being
+ // instantiated, and we haven't gotten around to instantiating this
+ // member yet. This can happen when the code uses forward declarations
+ // of member classes, and introduces ordering dependencies via
+ // template instantiation.
+ Diag(Loc, diag::err_member_not_yet_instantiated)
+ << D->getDeclName()
+ << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
+ Diag(D->getLocation(), diag::note_non_instantiated_member_here);
+ } else {
+ // We should have found something, but didn't.
+ llvm_unreachable("Unable to find instantiation of declaration!");
+ }
+ }
+
D = Result;
}