Fixes rust-lang#69977 When we parse a chain of method calls like `foo.a().b().c()`, each `MethodCallExpr` gets assigned a span that starts at the beginning of the call chain (`foo`). While this is useful for diagnostics, it means that `Location::caller` will return the same location for every call in a call chain. This PR makes us separately record the span of the function name and arguments for a method call (e.g. `b()` in `foo.a().b().c()`). This `Span` is passed through HIR lowering and MIR building to `TerminatorKind::Call`, where it is used in preference to `Terminator.source_info.span` when determining `Location::caller`. This new span is also useful for diagnostics where we want to emphasize a particular method call - for an example, see rust-lang#72389 (comment)

Commits

Commits on Jun 10, 2020

Track span of function in method calls, and use this in #[track_caller]

Update Clippy for MethodCall changes

Fix pprust-expr-roundtrip

Add doc comments

Clippy fixes

Fix test