rust/compiler/rustc_middle
bors 80926fc409 Auto merge of #86368 - michaelwoerister:lexing-ice, r=davidtwco
Disambiguate between SourceFiles from different crates even if they have the same path

This PR fixes an ICE that can occur when the compiler encounters a source file that is part of both the local crate and an upstream crate:

1. While importing source files from an upstream crate the compiler creates a `SourceFile` entry for `foo.rs` in the `SourceMap`. Since this is an imported source file its `src` field is `None`.
2. At a later point the parser encounters `foo.rs` again. It tells the `SourceMap` to load the file but because we already have an entry for `foo.rs` the `SourceMap` will return the existing version with `src == None`.
3. The parser proceeds under the assumption that `src.is_some()` and panics when actually trying to use the file's contents.

This PR fixes the issue by adding the source file's associated `CrateNum` to the `SourceMap`'s interning key. As a consequence the two instances of the file will each have a separate entry in the `SourceMap`. They just happen to share the same file path. This approach seemed less problematic to me than trying to mutate the `SourceFile` after it had already been created.

Another, more involved, approach might be to merge the `src` and the `external_src` field.

Fixes #85955
2021-06-22 14:53:58 +00:00
..
benches mv compiler to compiler/ 2020-08-30 18:45:07 +03:00
src Auto merge of #86368 - michaelwoerister:lexing-ice, r=davidtwco 2021-06-22 14:53:58 +00:00
Cargo.toml Update to rustc-rayon 0.3.1 2021-03-10 17:53:35 -08:00
README.md mv compiler to compiler/ 2020-08-30 18:45:07 +03:00

For more information about how rustc works, see the rustc dev guide.