Fix crash in use-self lint

[ghost]

Fixes #4727

changelog: Fix crash in use-self lint

[ghost]

The compiler creates paths for the range syntax (..) during lowering. We shouldn't check these paths. The only way I could find to test for them was to check for dummy spans on the path segments.

I based the setup for the ice test on the "backtrace-debuginfo" ui test in the compiler. I don't like creating an ignored test for the submodule but I couldn't find a better way.

There is another problem in the code related to this issue around primitive types that don't have a def_id. I'll document it in another issue later.

[ghost]

Just noticed some problems with this PR. I'll update later...

[ghost]

This should be good now. Just waiting on build fixes to be merged.

[flip1995]

You can move this file in the auxiliary dir, so you don't have to ignore it, like

rust-clippy/tests/ui/auxiliary/use_self_macro.rs

Line 1 in 43a3796

macro_rules! use_self {

which is used in

rust-clippy/tests/ui/ice-4671.rs

Lines 4 to 5 in 43a3796

	#[path = "auxiliary/use_self_macro.rs"]
	mod use_self_macro;

[flip1995]

@bors r+

Thanks!

[bors]

📌 Commit cc6e27f has been approved by flip1995

[bors]

⌛ Testing commit cc6e27f with merge 9c45480...

[flip1995]

@bors retry, to prioritize rustup

[flip1995]

@bors retry

[flip1995]

@bors treeclosed-

[bors]

⌛ Testing commit cc6e27f with merge b0b3dc6...

[bors]

☀️ Test successful - checks-travis, status-appveyor
Approved by: flip1995
Pushing b0b3dc6 to master...