Commit Graph

2 Commits

Author SHA1 Message Date
James Y Knight ccc4d83cda [ObjC] Diagnose implicit type coercion from ObjC 'Class' to object
pointer types.

For example, in Objective-C mode, the initialization of 'x' in:
```
  @implementation MyType
  + (void)someClassMethod {
    MyType *x = self;
  }
  @end
```
is correctly diagnosed with an incompatible-pointer-types warning, but
in Objective-C++ mode, it is not diagnosed at all -- even though
incompatible pointer conversions generally become an error in C++.

This patch fixes that oversight, allowing implicit conversions
involving Class only to/from unqualified-id, and between qualified and
unqualified Class, where the protocols are compatible.

Note that this does change some behaviors in Objective-C, as well, as
shown by the modified tests.

Of particular note is that assignment from from 'Class<MyProtocol>' to
'id<MyProtocol>' now warns. (Despite appearances, those are not
compatible types. 'Class<MyProtocol>' is not expected to have instance
methods defined by 'MyProtocol', while 'id<MyProtocol>' is.)

Differential Revision: https://reviews.llvm.org/D67983

llvm-svn: 375125
2019-10-17 15:27:04 +00:00
James Y Knight 1c982af059 [ObjC] Add some additional test cases around pointer conversions.
This is especially important for Objective-C++, which is entirely
missing this testing at the moment.

This annotates with "FIXME" the cases which I change in the next
patch -- I primarily wanted to document the current state of things so
that the effect of the code change is made clear.

Differential Revision: https://reviews.llvm.org/D67982

llvm-svn: 375124
2019-10-17 15:18:59 +00:00