is that we need more information to decide the exact conditions for whether
one ObjCObjectPointer is an acceptable return/parameter override for another,
so we're going to disable that entire class of warning for now. The
"forward developement" warning category, -Wmethod-signatures, can receive
unrestricted feature work, and when we're happy with how it acts, we'll
turn it on by default.
This is a pretty conservative change, and nobody's totally content with it.
llvm-svn: 117524
covariant/contravariant overrides and implementations, but do so under
control of a new flag (-Wno-objc-covariant-overrides, which yes does cover
contravariance too).
*At least* the covariance cases will probably be enabled by default shortly,
but that's not totally uncontroversial.
llvm-svn: 117346
A common idiom in Objective-C is to provide a definition of a method in a subclass that returns a more-specified version of an object than the superclass. This does not violate the principle of substitutability, because you can always use the object returned by the subclass anywhere that you could use the type returned by the superclass. It was, however, generating warnings with clang, leading people to believe that semantically correct code was incorrect and requiring less accurate type specification and explicit down-casts (neither of which is a good thing to encourage).
This change ensures that any method definition has parameter and return types that make it accept anything that something conforming to the declaration may pass and return something that the caller will expect, but allows stricter definitions.
llvm-svn: 117271
John McCall