[Sema] Fix diagnostic for addr spaces in reference binding

[Anastasia]

Summary

Extend reference binding behavior to account for address spaces. This change also fixes the diagnostic wording (for qualifier mismatch in reference binding) and simplifies it by using Qualifiers print method.

This patch is rebased from https://reviews.llvm.org/D58060 that got lost somehow.

[rjmccall]

I like this wording of the diagnostic better in general. Could you make the diagnostic change in a separate patch and then fix the address-space problem? Both patches are approved.

cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td

 def err_lvalue_reference_bind_to_temporary : Error<
   "%select{non-const|volatile}0 lvalue reference %diff{to type $ cannot bind "
   "to a temporary of type $|cannot bind to incompatible temporary}1,2">;
 def err_lvalue_reference_bind_to_unrelated : Error<
   "%select{non-const|volatile}0 lvalue reference "
   "%diff{to type $ cannot bind to a value of unrelated type $|"
   "cannot bind to a value of unrelated type}1,2">;
 def err_reference_bind_drops_quals : Error<
-  "binding value %diff{of type $ to reference to type $|to reference}0,1 "
-  "drops %select{<<ERROR>>|'const'|'restrict'|'const' and 'restrict'|"
-  "'volatile'|'const' and 'volatile'|'restrict' and 'volatile'|"
-  "'const', 'restrict', and 'volatile'}2 qualifier%plural{1:|2:|4:|:s}2">;
+  "binding reference %diff{of type $ to value of type $|to value}0,1 "
+  "drops %2 qualifier%plural{1:|2:|4:|:s}3">;
 def err_reference_bind_failed : Error<
   "reference %diff{to %select{type|incomplete type}1 $ could not bind to an "
   "%select{rvalue|lvalue}2 of type $|could not bind to %select{rvalue|lvalue}2 of "
   "incompatible type}0,3">;
 def err_reference_bind_temporary_addrspace : Error<
   "reference of type %0 cannot bind to a temporary object because of "
   "address space mismatch">;
 def err_reference_bind_init_list : Error<

cfe/trunk/lib/Sema/SemaInit.cpp

bool InitializationSequence::Diagnose(Sema &S,
 
   case FK_ReferenceInitDropsQualifiers: {
     QualType SourceType = OnlyArg->getType();
     QualType NonRefType = DestType.getNonReferenceType();
     Qualifiers DroppedQualifiers =
         SourceType.getQualifiers() - NonRefType.getQualifiers();
 
     S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
-      << SourceType
       << NonRefType
+      << SourceType
+      << Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
       << DroppedQualifiers.getCVRQualifiers()
       << Args[0]->getSourceRange();
     break;
   }
 
   case FK_ReferenceInitFailed:
     S.Diag(Kind.getLocation(), diag::err_reference_bind_failed)
       << DestType.getNonReferenceType()

cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5-0x.cpp

namespace std_example_2 {
   } x;
   const A& r = x;
   int&& rri = static_cast<int&&>(i);
   B&& rrb = x;
   int&& rri2 = X(); // expected-error{{no viable conversion from 'std_example_2::X' to 'int'}}
 
   const double& rcd2 = 2;
   double&& rrd = 2;
-  const volatile int cvi = 1; 
-  const int& r2 = cvi; // expected-error{{binding value of type 'const volatile int' to reference to type 'const int' drops 'volatile' qualifier}}
+  const volatile int cvi = 1;
+  const int& r2 = cvi; // expected-error{{binding reference of type 'const int' to value of type 'const volatile int' drops 'volatile' qualifier}}
 
   double d;
   double&& rrd2 = d; // expected-error{{rvalue reference to type 'double' cannot bind to lvalue of type 'double'}}
   double&& rrd3 = i;
 }
 
 namespace argument_passing {
   void base_rvalue_ref(Base&&);

cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5-var.cpp

void bind_lvalue_to_lvalue(Base b, Derived d,
   long &lr = i; // expected-error{{non-const lvalue reference to type 'long' cannot bind to a value of unrelated type 'int'}}
 }
 
 void bind_lvalue_quals(volatile Base b, volatile Derived d,
                        volatile const Base bvc, volatile const Derived dvc,
                        volatile const int ivc) {
   volatile Base &bvr1 = b;
   volatile Base &bvr2 = d;
-  volatile Base &bvr3 = bvc; // expected-error{{binding value of type 'const volatile Base' to reference to type 'volatile Base' drops 'const' qualifier}}
-  volatile Base &bvr4 = dvc; // expected-error{{binding value of type 'const volatile Derived' to reference to type 'volatile Base' drops 'const' qualifier}}
-  
-  volatile int &ir = ivc; // expected-error{{binding value of type 'const volatile int' to reference to type 'volatile int' drops 'const' qualifier}}
+  volatile Base &bvr3 = bvc; // expected-error{{binding reference of type 'volatile Base' to value of type 'const volatile Base' drops 'const' qualifier}}
+  volatile Base &bvr4 = dvc; // expected-error{{binding reference of type 'volatile Base' to value of type 'const volatile Derived' drops 'const' qualifier}}
+  volatile int &ir = ivc; // expected-error{{binding reference of type 'volatile int' to value of type 'const volatile int' drops 'const' qualifier}}
 
   const volatile Base &bcvr1 = b;
   const volatile Base &bcvr2 = d;
 }
 
 void bind_lvalue_to_rvalue() {
   Base &br1 = Base(); // expected-error{{non-const lvalue reference to type 'Base' cannot bind to a temporary of type 'Base'}}
   Base &br2 = Derived(); // expected-error{{non-const lvalue reference to type 'Base' cannot bind to a temporary of type 'Derived'}}

 void bind_const_lvalue_to_rvalue() {
   const Base &br1 = create<Base>();
   const Base &br2 = create<Derived>();
   const Derived &dr1 = create<Base>(); // expected-error{{no viable conversion}}
 
   const Base &br3 = create<const Base>();
   const Base &br4 = create<const Derived>();
 
-  const Base &br5 = create<const volatile Base>(); // expected-error{{binding value of type 'const volatile Base' to reference to type 'const Base' drops 'volatile' qualifier}}
-  const Base &br6 = create<const volatile Derived>(); // expected-error{{binding value of type 'const volatile Derived' to reference to type 'const Base' drops 'volatile' qualifier}}
+  const Base &br5 = create<const volatile Base>();    // expected-error{{binding reference of type 'const Base' to value of type 'const volatile Base' drops 'volatile' qualifier}}
+  const Base &br6 = create<const volatile Derived>(); // expected-error{{binding reference of type 'const Base' to value of type 'const volatile Derived' drops 'volatile' qualifier}}
 
   const int &ir = create<int>();
 }
 
 // Second bullet: const lvalue reference binds to the result of a conversion.
 void bind_const_lvalue_to_class_conv_temporary() {
   const Base &br1 = ConvertibleToBase();
   const Base &br2 = ConvertibleToDerived();
 }
 void bind_lvalue_to_conv_rvalue_ambig(ConvertibleToBothDerived both) {
   const Derived &dr1 = both;
   const Base &br1 = both; // expected-error{{reference initialization of type 'const Base &' with initializer of type 'ConvertibleToBothDerived' is ambiguous}}
 }

cfe/trunk/test/CXX/expr/expr.post/expr.static.cast/p3-p4-0x.cpp

void test(A &a, B &b) {
   A &&ar1 = static_cast<A&&>(prvalue<B>());
   A &&ar2 = static_cast<A&&>(lvalue<C>());
   A &&ar3 = static_cast<A&&>(xvalue<C>());
   A &&ar4 = static_cast<A&&>(prvalue<C>());
   A &&ar5 = static_cast<A&&>(lvalue<D>());
   A &&ar6 = static_cast<A&&>(xvalue<D>());
   A &&ar7 = static_cast<A&&>(prvalue<D>());
 
-  A &&ar8 = static_cast<A&&>(prvalue<const A>()); // expected-error {{binding value of type 'const A' to reference to type 'A' drops 'const' qualifier}}
-  A &&ar9 = static_cast<A&&>(lvalue<const A>()); // expected-error {{cannot cast from lvalue of type 'const A'}}
+  A &&ar8 = static_cast<A&&>(prvalue<const A>()); // expected-error {{binding reference of type 'A' to value of type 'const A' drops 'const' qualifier}}
+  A &&ar9 = static_cast<A&&>(lvalue<const A>());  // expected-error {{cannot cast from lvalue of type 'const A'}}
   A &&ar10 = static_cast<A&&>(xvalue<const A>()); // expected-error {{cannot cast from rvalue of type 'const A'}}
 
   const A &&ar11 = static_cast<const A&&>(prvalue<A>());
   const A &&ar12 = static_cast<const A&&>(prvalue<B>());
   const A &&ar13 = static_cast<const A&&>(lvalue<C>());
   const A &&ar14 = static_cast<const A&&>(xvalue<C>());
   const A &&ar15 = static_cast<const A&&>(prvalue<C>());
   const A &&ar16 = static_cast<const A&&>(lvalue<D>());
 
-  const A &&ar17 = static_cast<const A&&>(prvalue<A const volatile>()); // expected-error {{binding value of type 'const volatile A' to reference to type 'const A' drops 'volatile' qualifier}}
+  const A &&ar17 = static_cast<const A&&>(prvalue<A const volatile>()); // expected-error {{binding reference of type 'const A' to value of type 'const volatile A' drops 'volatile' qualifier}}
 }

cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p16.cpp

void test_capture(X x) {
 
   [x] {
     [&x] {
       [x] { // expected-error{{call to deleted constructor of 'const X'}}
       }();
     }();
   }();
 
-  int a; 
-  [=]{ 
-    [&] { 
-      int &x = a;  // expected-error{{binding value of type 'const int' to reference to type 'int' drops 'const' qualifier}}
-      int &x2 = a;  // expected-error{{binding value of type 'const int' to reference to type 'int' drops 'const' qualifier}}
-    }(); 
-  }(); 
+  int a;
+  [=] {
+    [&] {
+      int &x = a;  // expected-error{{binding reference of type 'int' to value of type 'const int' drops 'const' qualifier}}
+      int &x2 = a; // expected-error{{binding reference of type 'int' to value of type 'const int' drops 'const' qualifier}}
+    }();
+  }();
 
-  [=]{ 
-    [&a] { 
-      [&] { 
-        int &x = a;  // expected-error{{binding value of type 'const int' to reference to type 'int' drops 'const' qualifier}}
-        int &x2 = a;  // expected-error{{binding value of type 'const int' to reference to type 'int' drops 'const' qualifier}}
+  [=] {
+    [&a] {
+      [&] {
+        int &x = a;  // expected-error{{binding reference of type 'int' to value of type 'const int' drops 'const' qualifier}}
+        int &x2 = a; // expected-error{{binding reference of type 'int' to value of type 'const int' drops 'const' qualifier}}
       }();
-    }(); 
-  }(); 
+    }();
+  }();
 }

cfe/trunk/test/Misc/diag-template-diffing.cpp

 struct is_const {
     constexpr operator int() const { return 10; }
 };
 
 using T = condition<(is_const())>;
 void foo(const T &t) {
   T &t2 = t;
 }
-// CHECK-ELIDE-NOTREE: binding value of type 'const condition<...>' to reference to type 'condition<...>' drops 'const' qualifier
+// CHECK-ELIDE-NOTREE: binding reference of type 'condition<...>' to value of type 'const condition<...>' drops 'const' qualifier
 }
 
 namespace BoolArgumentBitExtended {
 template <bool B> struct BoolT {};
 
 template <typename T> void foo(T) {}
 
 void test() {

cfe/trunk/test/SemaCXX/builtins-arm.cpp

 // RUN: %clang_cc1 -triple armv7 -fsyntax-only -verify %s
 
 // va_list on ARM AAPCS is struct { void* __ap }.
 int test1(const __builtin_va_list &ap) {
-  return __builtin_va_arg(ap, int); // expected-error {{binding value of type 'const __builtin_va_list' to reference to type '__builtin_va_list' drops 'const' qualifier}}
+  return __builtin_va_arg(ap, int); // expected-error {{binding reference of type '__builtin_va_list' to value of type 'const __builtin_va_list' drops 'const' qualifier}}
 }

cfe/trunk/test/SemaCXX/err_reference_bind_drops_quals.cpp

 // RUN: %clang_cc1 -fsyntax-only -verify %s
 
 #define restrict __restrict__
 typedef int* ptr;
 void test1(ptr p, const ptr cp, restrict ptr rp, const restrict ptr crp,
            volatile ptr vp, const volatile ptr cvp, restrict volatile ptr rvp,
            const restrict volatile ptr crvp) {
   ptr& p1 = p;
-  ptr& p2 = cp; // expected-error {{drops 'const' qualifier}}
-  ptr& p3 = rp; // expected-error {{drops 'restrict' qualifier}}
-  ptr& p4 = crp; // expected-error {{drops 'const' and 'restrict' qualifiers}}
-  ptr& p5 = vp; // expected-error {{drops 'volatile' qualifier}}
-  ptr& p6 = cvp; // expected-error {{drops 'const' and 'volatile' qualifiers}}
-  ptr& p7 = rvp; // expected-error {{drops 'restrict' and 'volatile' qualifiers}}
-  ptr& p8 = crvp; // expected-error {{drops 'const', 'restrict', and 'volatile' qualifiers}}
+  ptr& p2 = cp;   // expected-error {{drops 'const' qualifier}}
+  ptr& p3 = rp;   // expected-error {{drops '__restrict' qualifier}}
+  ptr& p4 = crp;  // expected-error {{drops 'const __restrict' qualifiers}}
+  ptr& p5 = vp;   // expected-error {{drops 'volatile' qualifier}}
+  ptr& p6 = cvp;  // expected-error {{drops 'const volatile' qualifiers}}
+  ptr& p7 = rvp;  // expected-error {{drops 'volatile __restrict' qualifiers}}
+  ptr& p8 = crvp; // expected-error {{drops 'const volatile __restrict' qualifiers}}
 
   const ptr& cp1 = p;
   const ptr& cp2 = cp;
-  const ptr& cp3 = rp; // expected-error {{drops 'restrict' qualifier}}
-  const ptr& cp4 = crp; // expected-error {{drops 'restrict' qualifier}}
-  const ptr& cp5 = vp; // expected-error {{drops 'volatile' qualifier}}
-  const ptr& cp6 = cvp; // expected-error {{drops 'volatile' qualifier}}
-  const ptr& cp7 = rvp; // expected-error {{drops 'restrict' and 'volatile' qualifiers}}
-  const ptr& cp8 = crvp; // expected-error {{drops 'restrict' and 'volatile' qualifiers}}
+  const ptr& cp3 = rp;   // expected-error {{drops '__restrict' qualifier}}
+  const ptr& cp4 = crp;  // expected-error {{drops '__restrict' qualifier}}
+  const ptr& cp5 = vp;   // expected-error {{drops 'volatile' qualifier}}
+  const ptr& cp6 = cvp;  // expected-error {{drops 'volatile' qualifier}}
+  const ptr& cp7 = rvp;  // expected-error {{drops 'volatile __restrict' qualifiers}}
+  const ptr& cp8 = crvp; // expected-error {{drops 'volatile __restrict' qualifiers}}
 
   const volatile ptr& cvp1 = p;
   const volatile ptr& cvp2 = cp;
-  const volatile ptr& cvp3 = rp; // expected-error {{drops 'restrict' qualifier}}
-  const volatile ptr& cvp4 = crp; // expected-error {{drops 'restrict' qualifier}}
+  const volatile ptr& cvp3 = rp;  // expected-error {{drops '__restrict' qualifier}}
+  const volatile ptr& cvp4 = crp; // expected-error {{drops '__restrict' qualifier}}
   const volatile ptr& cvp5 = vp;
   const volatile ptr& cvp6 = cvp;
-  const volatile ptr& cvp7 = rvp; // expected-error {{drops 'restrict' qualifier}}
-  const volatile ptr& cvp8 = crvp; // expected-error {{drops 'restrict' qualifier}}
+  const volatile ptr& cvp7 = rvp;  // expected-error {{drops '__restrict' qualifier}}
+  const volatile ptr& cvp8 = crvp; // expected-error {{drops '__restrict' qualifier}}
 
   const restrict volatile ptr& crvp1 = p;
   const restrict volatile ptr& crvp2 = cp;
   const restrict volatile ptr& crvp3 = rp;
   const restrict volatile ptr& crvp4 = crp;
   const restrict volatile ptr& crvp5 = vp;
   const restrict volatile ptr& crvp6 = cvp;
   const restrict volatile ptr& crvp7 = rvp;
   const restrict volatile ptr& crvp8 = crvp;
 }

cfe/trunk/test/SemaCXX/references.cpp

void test4() {
   double& rd3 = i; // expected-error{{non-const lvalue reference to type 'double' cannot bind to a value of unrelated type 'int'}}
 
   const A& rca = fB();
 }
 
 void test5() {
   //  const double& rcd2 = 2; // rcd2 refers to temporary with value 2.0
   const volatile int cvi = 1;
-  const int& r = cvi; // expected-error{{binding value of type 'const volatile int' to reference to type 'const int' drops 'volatile' qualifier}}
+  const int& r = cvi; // expected-error{{binding reference of type 'const int' to value of type 'const volatile int' drops 'volatile' qualifier}}
 
 #if __cplusplus >= 201103L
-  const int& r2{cvi}; // expected-error{{binding value of type 'const volatile int' to reference to type 'const int' drops 'volatile' qualifier}}
+  const int& r2{cvi}; // expected-error{{binding reference of type 'const int' to value of type 'const volatile int' drops 'volatile' qualifier}}
 
   const int a = 2;
-  int& r3{a}; // expected-error{{binding value of type 'const int' to reference to type 'int' drops 'const'}}
+  int& r3{a}; // expected-error{{binding reference of type 'int' to value of type 'const int' drops 'const' qualifier}}
 
   const int&& r4{a}; // expected-error{{rvalue reference to type 'const int' cannot bind to lvalue of type 'const int'}}
 
   void func();
   void func(int);
   int &ptr1 = {func}; // expected-error{{address of overloaded function 'func' does not match required type 'int'}}
   int &&ptr2{func}; // expected-error{{address of overloaded function 'func' does not match required type 'int'}}
   // expected-note@-4{{candidate function}}