From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 22 Jul 2009 20:02:25 +0000 (+0000)
Subject: Improve template argument deduction for array types, so that a parameter
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9e9fae4b8af47c15696da4ea3c30102e3a035179;p=clang

Improve template argument deduction for array types, so that a parameter

  const T

can be matched with, e.g.,

  volatile int [5]




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76773 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index ac4e4b9b28..4e6d0f4dd1 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -341,6 +341,14 @@ DeduceTemplateArguments(ASTContext &Context,
         = Param->getAsTemplateTypeParmType()) {
     unsigned Index = TemplateTypeParm->getIndex();
 
+    // If the argument type is an array type, move the qualifiers up to the
+    // top level, so they can be matched with the qualifiers on the parameter.
+    // FIXME: address spaces, ObjC GC qualifiers
+    QualType ArgElementType = Arg;
+    while (const ArrayType *ArgArray = ArgElementType->getAs<ArrayType>())
+      ArgElementType = ArgArray->getElementType();
+    Arg = Arg.getWithAdditionalQualifiers(ArgElementType.getCVRQualifiers());
+                                          
     // The argument type can not be less qualified than the parameter
     // type.
     if (Param.isMoreQualifiedThan(Arg) && !(TDF & TDF_IgnoreQualifiers)) {
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index b58422b489..a75a8584d1 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -758,6 +758,7 @@ QualType TemplateTypeInstantiator::Instantiate(QualType T) const {
   //   which case the cv-qualifiers are ignored.
   // 
   // The same rule applies to function types.
+  // FIXME: what about address-space and Objective-C GC qualifiers?
   if (!Result.isNull() && T.getCVRQualifiers() &&
       !Result->isFunctionType() && !Result->isReferenceType())
     Result = Result.getWithAdditionalQualifiers(T.getCVRQualifiers());
diff --git a/test/SemaTemplate/temp_class_spec.cpp b/test/SemaTemplate/temp_class_spec.cpp
index 1a534236c8..da34350717 100644
--- a/test/SemaTemplate/temp_class_spec.cpp
+++ b/test/SemaTemplate/temp_class_spec.cpp
@@ -32,6 +32,35 @@ struct is_lvalue_reference<T&> {
 int lvalue_ref0[is_lvalue_reference<int>::value? -1 : 1];
 int lvalue_ref1[is_lvalue_reference<const int&>::value? 1 : -1];
 
+template<typename T>
+struct is_const {
+  static const bool value = false;
+};
+
+template<typename T>
+struct is_const<const T> {
+  static const bool value = true;
+};
+
+int is_const0[is_const<int>::value? -1 : 1];
+int is_const1[is_const<const int>::value? 1 : -1];
+int is_const2[is_const<const volatile int>::value? 1 : -1];
+
+template<typename T>
+struct is_volatile {
+  static const bool value = false;
+};
+
+template<typename T>
+struct is_volatile<volatile T> {
+  static const bool value = true;
+};
+
+int is_volatile0[is_volatile<int>::value? -1 : 1];
+int is_volatile1[is_volatile<volatile int>::value? 1 : -1];
+int is_volatile2[is_volatile<const volatile int>::value? 1 : -1];
+int is_volatile3[is_volatile<volatile char[3]>::value? 1 : -1];
+                 
 template<typename T, typename U>
 struct is_same {
   static const bool value = false;