[PATCH] D58346: [Sema] Change addr space diagnostics in casts to follow C++ style

[Anastasia Stulova via Phabricator via cfe-commits]

Anastasia marked an inline comment as done.
Anastasia added inline comments.


================
Comment at: lib/Sema/SemaCast.cpp:2309
+    auto DestPointeeTypeWithoutAS = Self.Context.removeAddrSpaceQualType(
+        DestPointeeType.getCanonicalType());
+    return Self.Context.hasSameType(SrcPointeeTypeWithoutAS,
----------------
Anastasia wrote:
> ebevhan wrote:
> > Maybe I'm mistaken, but won't getting the canonical type here drop qualifiers (like cv) in nested pointers? If so, an addrspace_cast might strip qualifiers by mistake.
> Yes, indeed I will need to extend this to nested pointers when we are ready. But for now I can try to change this bit... however I am not sure it will work w/o canonical types when we have typedef. I will try to create an example and see.
I checked the canonical type does preserve the qualifiers correctly.

Here is the AST dump of the following C type `mytype const __generic*` where  `typedef  __generic int* mytype;`.


```
PointerType 0x204d3b0 'const __generic mytype *'
`-QualType 0x204d369 'const __generic mytype' const __generic
  `-TypedefType 0x204d320 'mytype' sugar
    |-Typedef 0x204d1b0 'mytype'
    `-PointerType 0x204d170 '__generic int *'
      `-QualType 0x204d158 '__generic int' __generic
        `-BuiltinType 0x2009750 'int'
```

and it's canonical representation in AST is:

```
PointerType 0x204d380 '__generic int *const __generic *'
`-QualType 0x204d349 '__generic int *const __generic' const __generic
  `-PointerType 0x204d170 '__generic int *'
    `-QualType 0x204d158 '__generic int' __generic
      `-BuiltinType 0x2009750 'int'
```

So using canonical type will just simply handling of nested pointer chain by avoiding special casing typedefs. We won't loose any qualifiers.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D58346/new/

https://reviews.llvm.org/D58346