Port r163224 to C++.

The motivation is to fix a crash on

  struct S {} s;
  Foo S::~S() { s.~S(); }

What was happening here was that S::~S() was marked as invalid since its
return type is invalid, and as a consequence CheckFunctionDeclaration() wasn't
called and S::~S() didn't get merged into S's implicit destructor.  This way,
the class ended up with two destructors, which confused the overload printer
when it suddenly had to print two possible destructors for `s.~S()`.

In addition to fixing the crash, this change also seems to improve diagnostics
in a few other places, see test changes.

Crash found by SLi's bot.

llvm-svn: 229639

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index ae18d9cbdb4..d351b4841f8 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7418,7 +7418,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
       D.setRedeclaration(CheckFunctionDeclaration(S, NewFD, Previous,
                                                   isExplicitSpecialization));
     else if (!Previous.empty())
-      // Make graceful recovery from an invalid redeclaration.
+      // Recover gracefully from an invalid redeclaration.
       D.setRedeclaration(true);
     assert((NewFD->isInvalidDecl() || !D.isRedeclaration() ||
             Previous.getResultKind() != LookupResult::FoundOverloaded) &&
@@ -7559,6 +7559,9 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
       if (!NewFD->isInvalidDecl())
         D.setRedeclaration(CheckFunctionDeclaration(S, NewFD, Previous,
                                                     isExplicitSpecialization));
+      else if (!Previous.empty())
+        // Recover gracefully from an invalid redeclaration.
+        D.setRedeclaration(true);
     }
 
     assert((NewFD->isInvalidDecl() || !D.isRedeclaration() ||