bjoernager/rust
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pretty: trim paths of unique symbols

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If a symbol name can only be imported from one place for a type, and
as long as it was not glob-imported anywhere in the current crate, we
can trim its printed path and print only the name.

This has wide implications on error messages with types, for example,
shortening `std::vec::Vec` to just `Vec`, as long as there is no other
`Vec` importable anywhere.

This adds a new '-Z trim-diagnostic-paths=false' option to control this
feature.

On the good path, with no diagnosis printed, we should try to avoid
issuing this query, so we need to prevent trimmed_def_paths query on
several cases.

This change also relies on a previous commit that differentiates
between `Debug` and `Display` on various rustc types, where the latter
is trimmed and presented to the user and the former is not.
This commit is contained in:
Dan Aloni 2020-09-02 10:40:56 +03:00
parent 7b2deb5628
commit 07e7823c01
1325 changed files with 4806 additions and 4546 deletions
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6
compiler/rustc_mir/src/const_eval/eval_queries.rs
View file

@ -10,6 +10,7 @@ use rustc_hir::def::DefKind;
use rustc_middle::mir;
use rustc_middle::mir::interpret::ErrorHandled;
use rustc_middle::traits::Reveal;
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::{self, subst::Subst, TyCtxt};
use rustc_span::source_map::Span;
use rustc_target::abi::{Abi, LayoutOf};
@ -33,7 +34,8 @@ fn eval_body_using_ecx<'mir, 'tcx>(
assert!(!layout.is_unsized());
let ret = ecx.allocate(layout, MemoryKind::Stack);
let name = ty::tls::with(|tcx| tcx.def_path_str(cid.instance.def_id()));
let name =
with_no_trimmed_paths(|| ty::tls::with(|tcx| tcx.def_path_str(cid.instance.def_id())));
let prom = cid.promoted.map_or(String::new(), |p| format!("::promoted[{:?}]", p));
trace!("eval_body_using_ecx: pushing stack frame for global: {}{}", name, prom);
@ -290,7 +292,7 @@ pub fn const_eval_raw_provider<'tcx>(
// The next two lines concatenated contain some discussion:
// https://rust-lang.zulipchat.com/#narrow/stream/146212-t-compiler.2Fconst-eval/
// subject/anon_const_instance_printing/near/135980032
let instance = key.value.instance.to_string();
let instance = with_no_trimmed_paths(|| key.value.instance.to_string());
trace!("const eval: {:?} ({})", key, instance);
}