Fix PR6149 by looking at the qualifiers on the referred to type for non-type

reference template arguments. Adds test cases for the cv-quals of reference
arguments.

llvm-svn: 95217

2 files changed, 73 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 13cf7833914..6a094e48e8f 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -2732,7 +2732,8 @@ bool Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
     assert(ParamRefType->getPointeeType()->isObjectType() &&
            "Only object references allowed here");
 
-    if (!Context.hasSameUnqualifiedType(ParamRefType->getPointeeType(), ArgType)) {
+    QualType ReferredType = ParamRefType->getPointeeType();
+    if (!Context.hasSameUnqualifiedType(ReferredType, ArgType)) {
       Diag(Arg->getSourceRange().getBegin(),
            diag::err_template_arg_no_ref_bind)
         << InstantiatedParamType << Arg->getType()
@@ -2742,7 +2743,7 @@ bool Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
     }
 
     unsigned ParamQuals
-      = Context.getCanonicalType(ParamType).getCVRQualifiers();
+      = Context.getCanonicalType(ReferredType).getCVRQualifiers();
     unsigned ArgQuals = Context.getCanonicalType(ArgType).getCVRQualifiers();
 
     if ((ParamQuals | ArgQuals) != ParamQuals) {
diff --git a/clang/test/CXX/temp/temp.arg/temp.arg.nontype/p5.cpp b/clang/test/CXX/temp/temp.arg/temp.arg.nontype/p5.cpp
new file mode 100644
index 00000000000..6d1d39c33c5
--- /dev/null
+++ b/clang/test/CXX/temp/temp.arg/temp.arg.nontype/p5.cpp
@@ -0,0 +1,70 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// C++0x [temp.arg.nontype] p5:
+//   The following conversions are performed on each expression used as
+//   a non-type template-argument. If a non-type template-argument cannot be
+//   converted to the type of the corresponding template-parameter then the
+//   program is ill-formed.
+//     -- for a non-type template-parameter of integral or enumeration type,
+//        integral promotions (4.5) and integral conversions (4.7) are applied.
+//     -- for a non-type template-parameter of type pointer to object,
+//        qualification conversions (4.4) and the array-to-pointer conversion
+//        (4.2) are applied; if the template-argument is of type
+//        std::nullptr_t, the null pointer conversion (4.10) is applied.
+//     -- For a non-type template-parameter of type reference to object, no
+//        conversions apply. The type referred to by the reference may be more
+//        cv-qualified than the (otherwise identical) type of the
+//        template-argument. The template-parameter is bound directly to the
+//        template-argument, which shall be an lvalue.
+namespace reference_parameters {
+  template <int& N> struct S0 { }; // expected-note 3 {{template parameter is declared here}}
+  template <const int& N> struct S1 { }; // expected-note 2 {{template parameter is declared here}}
+  template <volatile int& N> struct S2 { }; // expected-note 2 {{template parameter is declared here}}
+  template <const volatile int& N> struct S3 { };
+  int i;
+  extern const int ci;
+  volatile int vi;
+  extern const volatile int cvi;
+  void test() {
+    S0<i> s0;
+    S0<ci> s0c; // expected-error{{reference binding of non-type template parameter of type 'int &' to template argument of type 'int const' ignores qualifiers}}
+    S0<vi> s0v; // expected-error{{reference binding of non-type template parameter of type 'int &' to template argument of type 'int volatile' ignores qualifiers}}
+    S0<cvi> s0cv; // expected-error{{reference binding of non-type template parameter of type 'int &' to template argument of type 'int const volatile' ignores qualifiers}}
+
+    S1<i> s1;
+    S1<ci> s1c;
+    S1<vi> s1v; // expected-error{{reference binding of non-type template parameter of type 'int const &' to template argument of type 'int volatile' ignores qualifiers}}
+    S1<cvi> s1cv; // expected-error{{reference binding of non-type template parameter of type 'int const &' to template argument of type 'int const volatile' ignores qualifiers}}
+
+    S2<i> s2;
+    S2<ci> s2c; // expected-error{{reference binding of non-type template parameter of type 'int volatile &' to template argument of type 'int const' ignores qualifiers}}
+    S2<vi> s2v;
+    S2<cvi> s2cv; // expected-error{{reference binding of non-type template parameter of type 'int volatile &' to template argument of type 'int const volatile' ignores qualifiers}}
+
+    S3<i> s3;
+    S3<ci> s3c;
+    S3<vi> s3v;
+    S3<cvi> s3cv;
+  }
+}
+
+//     -- For a non-type template-parameter of type pointer to function, the
+//        function-to-pointer conversion (4.3) is applied; if the
+//        template-argument is of type std::nullptr_t, the null pointer
+//        conversion (4.10) is applied. If the template-argument represents
+//        a set of overloaded functions (or a pointer to such), the matching
+//        function is selected from the set (13.4).
+//     -- For a non-type template-parameter of type reference to function, no
+//        conversions apply. If the template-argument represents a set of
+//        overloaded functions, the matching function is selected from the set
+//        (13.4).
+//     -- For a non-type template-parameter of type pointer to member function,
+//        if the template-argument is of type std::nullptr_t, the null member
+//        pointer conversion (4.11) is applied; otherwise, no conversions
+//        apply. If the template-argument represents a set of overloaded member
+//        functions, the matching member function is selected from the set
+//        (13.4).
+//     -- For a non-type template-parameter of type pointer to data member,
+//        qualification conversions (4.4) are applied; if the template-argument
+//        is of type std::nullptr_t, the null member pointer conversion (4.11)
+//        is applied.