[PATCH] D19175: Fix for PR27015 (variable template initialized with a generic lambda expression)

[Akira Hatanaka via cfe-commits]

ahatanak updated this revision to Diff 55453.
ahatanak added a comment.

Use ParseScopeFlags to clear the TemplateParamScope rather than calling setFlags directly.

I tried calling Init(AnyParent, F) is Scope::setFlags, but it caused a lot of test cases to fail, which I'm currently investigating.


http://reviews.llvm.org/D19175

Files:
  lib/Parse/ParseTemplate.cpp
  lib/Sema/SemaLambda.cpp
  lib/Sema/SemaTemplateInstantiateDecl.cpp
  test/CXX/temp/temp.arg/temp.arg.nontype/p1.cpp
  test/SemaCXX/vartemplate-lambda.cpp

Index: test/SemaCXX/vartemplate-lambda.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/vartemplate-lambda.cpp
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -std=c++14 -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+template <class> auto fn0 = [] {};
+template <typename> void foo0() { fn0<char>(); }
+
+template<typename T> auto fn1 = [](auto a) { return a + T(1); };
+
+template <typename X>
+int foo2() {
+  X a = 0x61;
+  fn1<char>(a);
+  return 0;
+}
+
+int main() {
+  foo2<int>();
+}
Index: test/CXX/temp/temp.arg/temp.arg.nontype/p1.cpp
===================================================================
--- test/CXX/temp/temp.arg/temp.arg.nontype/p1.cpp
+++ test/CXX/temp/temp.arg/temp.arg.nontype/p1.cpp
@@ -195,7 +195,7 @@
 namespace default_args {
 #ifdef CPP11ONLY
 namespace lambdas {
-template<int I = ([] { return 5; }())> //expected-error 2{{constant expression}} expected-note{{constant expression}}
+template<int I = ([] { return 5; }())> //expected-error {{constant expression}}
 int f();
 }
 #endif // CPP11ONLY
Index: lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3907,9 +3907,14 @@
       PushExpressionEvaluationContext(Sema::PotentiallyEvaluated, OldVar);
 
     // Instantiate the initializer.
-    ExprResult Init =
-        SubstInitializer(OldVar->getInit(), TemplateArgs,
-                         OldVar->getInitStyle() == VarDecl::CallInit);
+    ExprResult Init;
+
+    {
+      ContextRAII SwitchContext(*this, Var->getDeclContext());
+      Init = SubstInitializer(OldVar->getInit(), TemplateArgs,
+                              OldVar->getInitStyle() == VarDecl::CallInit);
+    }
+
     if (!Init.isInvalid()) {
       bool TypeMayContainAuto = true;
       Expr *InitExpr = Init.get();
Index: lib/Sema/SemaLambda.cpp
===================================================================
--- lib/Sema/SemaLambda.cpp
+++ lib/Sema/SemaLambda.cpp
@@ -814,8 +814,8 @@
   // The lambda-expression's closure type might be dependent even if its
   // semantic context isn't, if it appears within a default argument of a
   // function template.
-  if (Scope *TmplScope = CurScope->getTemplateParamParent())
-    if (!TmplScope->decl_empty())
+  if (auto *TmplScope = CurScope->getTemplateParamParent())
+    if (TmplScope->isTemplateParamScope())
       KnownDependent = true;
 
   // Determine the signature of the call operator.
Index: lib/Parse/ParseTemplate.cpp
===================================================================
--- lib/Parse/ParseTemplate.cpp
+++ lib/Parse/ParseTemplate.cpp
@@ -147,6 +147,9 @@
     }
   } while (Tok.isOneOf(tok::kw_export, tok::kw_template));
 
+  unsigned NewFlags = getCurScope()->getFlags() & ~Scope::TemplateParamScope;
+  ParseScopeFlags TemplateScopeFlags(this, NewFlags, isSpecialization);
+
   // Parse the actual template declaration.
   return ParseSingleDeclarationAfterTemplate(Context,
                                              ParsedTemplateInfo(&ParamLists,


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