rust/tests/rustdoc/issue-46271.rs

// hopefully this doesn't cause an ICE

pub fn foo() {
    extern crate std;
}
rustc: Filter out bogus extern crate warnings Rustdoc has for some time now used the "everybody loops" pass in the compiler to avoid typechecking and otherwise avoid looking at implementation details. In #46115 the placement of this pass was pushed back in the compiler to after macro expansion to ensure that it works with macro-expanded code as well. This in turn caused the regression in #46271. The bug here was that the resolver was producing `def_id` instances for "possibly unused extern crates" which would then later get processed during typeck to actually issue lint warnings. The problem was that after resolution these `def_id` nodes were actually removed from the AST by the "everybody loops" pass. This later, when we tried to take a look at `def_id`, caused the compiler to panic. The fix applied here is a bit of a heavy hammer which is to just, in this one case, ignore the `extern crate` lints if the `def_id` looks "bogus" in any way (basically if it looks like the node was removed after resolution). The real underlying bug here is probably that the "everybody loops" AST pass is being stressed to much beyond what it was originally intended to do, but this should at least fix the ICE for now... Closes #46271 2017-11-30 15:59:35 +00:00			`// hopefully this doesn't cause an ICE`

			`pub fn foo() {`
			`extern crate std;`
			`}`