From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Tue, 4 Dec 2018 22:26:32 +0000 (+0000)
Subject: Fix crash if an in-class explicit function specialization has explicit
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f8d79d803044ae1703b04edd8fc51f197e125499;p=clang

Fix crash if an in-class explicit function specialization has explicit
template arguments referring to template paramaeters.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@348313 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index f810c4eb31..f880d4616a 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2702,26 +2702,28 @@ Decl *TemplateDeclInstantiator::VisitUsingPackDecl(UsingPackDecl *D) {
 }
 
 Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
-                                     ClassScopeFunctionSpecializationDecl *Decl) {
+    ClassScopeFunctionSpecializationDecl *Decl) {
   CXXMethodDecl *OldFD = Decl->getSpecialization();
   CXXMethodDecl *NewFD =
     cast_or_null<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, nullptr, true));
   if (!NewFD)
     return nullptr;
 
-  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
-                        Sema::ForExternalRedeclaration);
-
-  TemplateArgumentListInfo TemplateArgs;
-  TemplateArgumentListInfo *TemplateArgsPtr = nullptr;
+  TemplateArgumentListInfo ExplicitTemplateArgs;
+  TemplateArgumentListInfo *ExplicitTemplateArgsPtr = nullptr;
   if (Decl->hasExplicitTemplateArgs()) {
-    TemplateArgs = Decl->templateArgs();
-    TemplateArgsPtr = &TemplateArgs;
+    if (SemaRef.Subst(Decl->templateArgs().getArgumentArray(),
+                      Decl->templateArgs().size(), ExplicitTemplateArgs,
+                      TemplateArgs))
+      return nullptr;
+    ExplicitTemplateArgsPtr = &ExplicitTemplateArgs;
   }
 
+  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
+                        Sema::ForExternalRedeclaration);
   SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
-  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, TemplateArgsPtr,
-                                                  Previous)) {
+  if (SemaRef.CheckFunctionTemplateSpecialization(
+          NewFD, ExplicitTemplateArgsPtr, Previous)) {
     NewFD->setInvalidDecl();
     return NewFD;
   }
diff --git a/test/SemaTemplate/member-specialization.cpp b/test/SemaTemplate/member-specialization.cpp
new file mode 100644
index 0000000000..ea30a7a0cd
--- /dev/null
+++ b/test/SemaTemplate/member-specialization.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -std=c++17 -verify %s
+// expected-no-diagnostics
+
+template<typename T, typename U> struct X {
+  template<typename V> const V &as() { return V::error; }
+  template<> const U &as<U>() { return u; }
+  U u;
+};
+int f(X<int, int> x) {
+  return x.as<int>();
+}