From 9d64f7264035d8d573abed95a15a07cb31796063 Mon Sep 17 00:00:00 2001
From: Dmitry Polukhin <dmitry.polukhin@gmail.com>
Date: Thu, 14 Apr 2016 09:52:06 +0000
Subject: [PATCH] [MSVC] Fix check for wchar_t type in case of -fno-wchar

The example below should work identically with and without compiler native
wchar_t support.

void foo(wchar_t * t = L"");

Differential Revision: http://reviews.llvm.org/D19056

llvm-svn: 266287
---
 clang/lib/Sema/SemaExprCXX.cpp  |  3 ++-
 clang/test/SemaCXX/no-wchar.cpp | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 4063464..0b09809 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -3040,7 +3040,8 @@ Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) {
               return (ToPointeeType->getKind() == BuiltinType::Char_U ||
                       ToPointeeType->getKind() == BuiltinType::Char_S);
             case StringLiteral::Wide:
-              return ToPointeeType->isWideCharType();
+              return Context.typesAreCompatible(Context.getWideCharType(),
+                                                QualType(ToPointeeType, 0));
           }
         }
       }
diff --git a/clang/test/SemaCXX/no-wchar.cpp b/clang/test/SemaCXX/no-wchar.cpp
index 291b657..b6dcddf 100644
--- a/clang/test/SemaCXX/no-wchar.cpp
+++ b/clang/test/SemaCXX/no-wchar.cpp
@@ -7,3 +7,24 @@ void foo(const wchar_t* x);
 void bar() {
   foo(L"wide string literal");
 }
+
+void foo1(wchar_t * t = L"");
+// expected-warning@-1 {{conversion from string literal to 'wchar_t *' (aka 'unsigned short *') is deprecated}}
+
+short *a = L"";
+// expected-error@-1 {{cannot initialize a variable of type 'short *' with an lvalue of type 'const unsigned short [1]'}}
+char *b = L"";
+// expected-error@-1 {{cannot initialize a variable of type 'char *' with an lvalue of type 'const unsigned short [1]'}}
+
+// NOTE: MSVC allows deprecated conversion in conditional expression if at least
+// one of the operand is a string literal but Clang doesn't allow it.
+wchar_t *c = true ? L"a" : L"";
+// expected-error@-1 {{cannot initialize a variable of type 'wchar_t *' (aka 'unsigned short *') with}}
+
+const wchar_t *d1 = 0;
+const wchar_t *d2 = 0;
+wchar_t *d = true ? d1 : d2;
+// expected-error@-1 {{cannot initialize a variable of type 'wchar_t *' (aka 'unsigned short *') with}}
+
+wchar_t* e = (const wchar_t*)L"";
+// expected-error@-1 {{cannot initialize a variable of type 'wchar_t *' (aka 'unsigned short *') with an rvalue of type 'const wchar_t *' (aka 'const unsigned short *')}}
-- 
2.7.4