Prevent module import inside @implementation

[Ben Langmuir]

Hi again,

This patch grew a bit to handle a bunch of other non-top-level contexts that imports might show up in.  Previously annot_module_include signaled an end-of-module, which the parser used to stop parsing in a bunch of places, and then you would get unfortunate diagnostics like this when the parser broke out of whatever context it was in

void foo() {
  #include “bar.h” // error missing }
} // error extraneous closing brace (})


I wasn’t sure how to say ‘must be at top level’ in the diagnostic.  I only found one existing diagnostic that mentions ‘top level’, but several that refer to ‘file scope’, so I went with the latter.  I’m happy to change that if there is a convention I didn’t pick up on.

Ben

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On Feb 4, 2014, at 8:48 AM, Douglas Gregor <dgregor at apple.com> wrote:

> 
> On Feb 4, 2014, at 8:19 AM, Ben Langmuir <blangmuir at apple.com> wrote:
> 
>> 
>> On Feb 3, 2014, at 4:51 PM, Douglas Gregor <dgregor at apple.com> wrote:
>> 
>>> 
>>> On Feb 3, 2014, at 2:32 PM, Ben Langmuir <blangmuir at apple.com> wrote:
>>> 
>>>> Based on a suggestion from Jordan I’ve dropped the extra note, which will be on the same location anyway, and added that information into the error diagnostic.  I would have liked to say "treating #include ...” instead of  "treating directive …", but after the preprocessor/lexer this information is lost and I don’t see a nice way to pass it on to the parser.
>>> 
>>> There’s an ugly way to pass it on to the parser… you have a couple low bits in the token’s annotation value to record #include vs. #import vs. #include_next.
>> 
>> To be clear, are you suggesting making Token::PtrData a PointerIntPair?
> 
> Token::PtrData is an opaque pointer with different meanings for different annotation token kinds. For a module import token, that could be PointerIntPair<Module *, 2, IncludeDirectiveKind>.
> 
> 	- Doug
>