[PATCH] D17166: [Sema] More changes to fix Objective-C fallout from r249995.

[Bob Wilson via cfe-commits]

bob.wilson created this revision.
bob.wilson added reviewers: cfe-commits, george.burgess.iv, doug.gregor, rsmith.
Herald added a subscriber: mcrosier.

This is a follow-up to PR26085. That was fixed in r257710 but the testcase there was incomplete. There is a related issue where the overload resolution for Objective-C incorrectly picks a method that is not valid without a bridge cast. The call to Sema::CheckSingleAssignmentConstraints that was added to SemaOverload.cpp's IsStandardConversion() function does not catch that case and reports that the method is Compatible even when it is not.
    
The root cause here is that various Objective-C-related functions in Sema do not consistently return a value to indicate whether there was an error. This was fine in the past because they would report diagnostics when needed, but r257710 changed them to suppress reporting diagnostics when checking during overload resolution.

This patch adds a new ACR_error result to the ARCConversionResult enum and updates Sema::CheckObjCARCConversion to return that value when there is an error. Most of the calls to that function do not check the return value, so adding this new result does not affect them. The one exception is in SemaCast.cpp where it specifically checks for ACR_unbridged, so that is also OK. The call in Sema::CheckSingleAssignmentConstraints can then check for an ACR_okay result and identify assignments as Incompatible. To preserve the existing behavior, it only changes the return value to Incompatible when the new Diagnose argument (from r257710) is false.

Similarly, the CheckObjCBridgeRelatedConversions and ConversionToObjCStringLiteralCheck need to identify when an assignment is Incompatible. Those functions already return appropriate values but they need some fixes related to the new Diagnose argument.

http://reviews.llvm.org/D17166

Files:
  include/clang/Sema/Sema.h
  lib/Sema/SemaExpr.cpp
  lib/Sema/SemaExprObjC.cpp
  test/SemaObjC/ovl-check.m

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