From: Nick Lewycky <nicholas@mxc.ca>
Date: Fri, 2 Jan 2015 01:33:12 +0000 (+0000)
Subject: Instantiation of a CXXMethodDecl may fail when the parameter type cannot be instantia... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=dd03a2db436ea1c99993bada326ee0fe570cf6d8;p=clang

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.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@225071 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 9ba9c14559..40e86175b2 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -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);
diff --git a/test/SemaTemplate/instantiate-method.cpp b/test/SemaTemplate/instantiate-method.cpp
index 58cb897955..4cc40af7e1 100644
--- a/test/SemaTemplate/instantiate-method.cpp
+++ b/test/SemaTemplate/instantiate-method.cpp
@@ -182,3 +182,16 @@ namespace SameSignatureAfterInstantiation {
   };
   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 }}
+  }
+}