Implement appropriate semantics for C++ casting and conversion when

dealing with address-space- and GC-qualified pointers. Previously,
these qualifiers were being treated just like cvr-qualifiers (in some
cases) or were completely ignored, leading to uneven behavior. For
example, const_cast would allow conversion between pointers to
different address spaces.

The new semantics are fairly simple: reinterpret_cast can be used to
explicitly cast between pointers to different address spaces
(including adding/removing addresss spaces), while
static_cast/dynamic_cast/const_cast do not tolerate any changes in the
address space. C-style casts can add/remove/change address spaces
through the reinterpret_cast mechanism. Other non-CVR qualifiers
(e.g., Objective-C GC qualifiers) work similarly.

As part of this change, I tweaked the "casts away constness"
diagnostic to use the term "casts away qualifiers". The term
"constness" actually comes from the C++ standard, despite the fact
that removing "volatile" also falls under that category. In Clang, we
also have restrict, address spaces, ObjC GC attributes, etc., so the
more general "qualifiers" is clearer.

llvm-svn: 129583

1 files changed, 3 insertions, 3 deletions

diff --git a/clang/test/SemaCXX/static-cast.cpp b/clang/test/SemaCXX/static-cast.cpp
index 46c6eee2c4e..7fb016ea86d 100644
--- a/clang/test/SemaCXX/static-cast.cpp
+++ b/clang/test/SemaCXX/static-cast.cpp
@@ -84,8 +84,8 @@ void t_529_5_8()
   (void)static_cast<C1&>(*((A*)0)); // expected-error {{cannot cast 'A' to 'C1 &' via virtual base 'B'}}
   (void)static_cast<D*>((A*)0); // expected-error {{cannot cast 'A *' to 'D *' via virtual base 'B'}}
   (void)static_cast<D&>(*((A*)0)); // expected-error {{cannot cast 'A' to 'D &' via virtual base 'B'}}
-  (void)static_cast<B*>((const A*)0); // expected-error {{static_cast from 'const A *' to 'B *' casts away constness}}
-  (void)static_cast<B&>(*((const A*)0)); // expected-error {{static_cast from 'const A' to 'B &' casts away constness}}
+  (void)static_cast<B*>((const A*)0); // expected-error {{static_cast from 'const A *' to 'B *' casts away qualifiers}}
+  (void)static_cast<B&>(*((const A*)0)); // expected-error {{static_cast from 'const A' to 'B &' casts away qualifiers}}
   (void)static_cast<E*>((A*)0); // expected-error {{cannot cast private base class 'A' to 'E'}}
   (void)static_cast<E&>(*((A*)0)); // expected-error {{cannot cast private base class 'A' to 'E'}}
   (void)static_cast<H*>((A*)0); // expected-error {{ambiguous cast from base 'A' to derived 'H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
@@ -119,7 +119,7 @@ void t_529_10()
 
   // Bad code below
 
-  (void)static_cast<int*>((const void*)0); // expected-error {{static_cast from 'const void *' to 'int *' casts away constness}}
+  (void)static_cast<int*>((const void*)0); // expected-error {{static_cast from 'const void *' to 'int *' casts away qualifiers}}
   (void)static_cast<void (*)()>((void*)0); // expected-error {{static_cast from 'void *' to 'void (*)()' is not allowed}}
 }