Unexpected macro syntax error when macro is in an expression

[xisui-MSFT]

Issue Type: Bug

Example:
#ifdef TEST
int func(int a,
#else
int func2(int a,
#endif
int b);

Error: #else and #endif are red since it thinks there are syntax errors.
Expected: parse correctly.

VS Code version: Code 1.26.0 (4e93618, 2018-08-13T16:29:31.933Z)
OS version: Windows_NT x64 10.0.17134

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz (8 x 3600)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: disabled_software rasterization: enabled video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled
Memory (System)	63.92GB (39.86GB free)
Process Argv	C:\Program Files\Microsoft VS Code\Code.exe
Screen Reader	no
VM	0%

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Editor indentation incorrect around tabbed function parameters (#35952)
• SignatureHelp gets confused when parameter labels are contained in function signature (#56337)

[mjbvz]

Nevermind on that caused-by-extension, this is a grammar issue.

We pull in our c/c++ grammar from here. Please file this issue upstream