r225071 - Instantiation of a CXXMethodDecl may fail when the parameter type cannot be instantiated. Do not crash in this case. Fixes PR22040!

[Nick Lewycky]

Author: nicholas
Date: Thu Jan  1 19:33:12 2015
New Revision: 225071

URL: http://llvm.org/viewvc/llvm-project?rev=225071&view=rev
Log:
Instantiation of a CXXMethodDecl may fail when the parameter type cannot be instantiated. Do not crash in this case. Fixes PR22040!

The FIXME in the test is caused by TemplateDeclInstantiator::VisitCXXRecordDecl
returning a nullptr instead of creating an invalid decl. This is a common
pattern across all of TemplateDeclInstantiator, so I'm not comfortable changing
it. The reason it's not invalid in the class template is due to support for an
MSVC extension, see r137573.

Modified:
    cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
    cfe/trunk/test/SemaTemplate/instantiate-method.cpp

Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=225071&r1=225070&r2=225071&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Thu Jan  1 19:33:12 2015
@@ -2360,8 +2360,10 @@ Decl * TemplateDeclInstantiator
 Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
                                      ClassScopeFunctionSpecializationDecl *Decl) {
   CXXMethodDecl *OldFD = Decl->getSpecialization();
-  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD,
-                                                                nullptr, true));
+  CXXMethodDecl *NewFD =
+    cast_or_null<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, nullptr, true));
+  if (!NewFD)
+    return nullptr;
 
   LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
                         Sema::ForRedeclaration);

Modified: cfe/trunk/test/SemaTemplate/instantiate-method.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/instantiate-method.cpp?rev=225071&r1=225070&r2=225071&view=diff
==============================================================================
--- cfe/trunk/test/SemaTemplate/instantiate-method.cpp (original)
+++ cfe/trunk/test/SemaTemplate/instantiate-method.cpp Thu Jan  1 19:33:12 2015
@@ -182,3 +182,16 @@ namespace SameSignatureAfterInstantiatio
   };
   S<const int> s; // expected-note {{instantiation}}
 }
+
+namespace PR22040 {
+  template <typename T> struct Foobar {
+    template <> void bazqux(typename T::type) {}  // expected-error {{cannot specialize a function 'bazqux' within class scope}} expected-error 2{{cannot be used prior to '::' because it has no members}}
+  };
+
+  void test() {
+    // FIXME: we should suppress the "no member" errors
+    Foobar<void>::bazqux();  // expected-error{{no member named 'bazqux' in }}  expected-note{{in instantiation of template class }}
+    Foobar<int>::bazqux();  // expected-error{{no member named 'bazqux' in }}  expected-note{{in instantiation of template class }}
+    Foobar<int>::bazqux(3);  // expected-error{{no member named 'bazqux' in }}
+  }
+}