[SR-485] C macros of the form ((long long)-1) should be imported

[lilyball]

Previous ID	SR-485
Radar	rdar://problem/20462344
Original Reporter	@lilyball
Type	Bug

Environment

Apple Swift version 2.1.1 (swiftlang-700.1.101.15 clang-700.1.81)
Target: x86_64-apple-darwin15.2.0

Additional Detail from JIRA

Votes	3
Component/s	Compiler
Labels	Bug, ClangImporter, Macros
Assignee	None
Priority	Medium

md5: 4f56b5e5a3db09cb27d77f8e3f9984fc

relates to:

• SR-141 Complex C header files macros are ignored
• SR-2402 Clang importer should import nullary function-like macros

Issue Description:

It turns out that NSURLResponseUnknownLength isn't exposed to Swift because the macro definition doesn't match Swift's rules for importable macros. The definition is:

#define NSURLResponseUnknownLength ((long long)-1)

This looks relatively straightforward, and should be simple enough that Swift can support. In general, any macro whose definition is the form ((SomeType)literal) should be importable.

[swift-ci]

Comment by Rick M (JIRA)

I'm having a similar problem with #define foo 1*2*3

[swift-ci]

Comment by Ky (JIRA)

This is necessary to complete the contract described in https://developer.apple.com/documentation/foundation/urlresponse/1413507-expectedcontentlength.

Without this, that contract cannot be fulfilled by API users