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Rollup merge of #116537 - gurry:116473-ice-sugg-overlap, r=compiler-errors

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Fix suggestion span involving wrongly placed generic arg on variant

Fixes #116473

The span computation was wrong. It went from the end of the variant to the end of the (wrongly placed) args. However, the variant lived in a different expansion and this resulted in a nonsensical span that overlaps with another and thereby leads to the ICE.

In the fix I've changed span computation to not be based on the location of the variant, but purely on the location of the args. I simply extend the start of the args span 2 positions to the left and that includes the `::` and that's all we need apparently.

This approach produces a correct span regardless of which macro/expansion the args reside in and where the variant is.
This commit is contained in:
Matthias Krüger 2023-10-09 16:26:01 +02:00 • committed by GitHub
commit 374c885f4a
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3 changed files with 356 additions and 3 deletions
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8
compiler/rustc_hir_analysis/src/astconv/mod.rs
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@ -36,7 +36,7 @@ use rustc_middle::ty::{
use rustc_session::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
use rustc_span::edit_distance::find_best_match_for_name;
use rustc_span::symbol::{kw, Ident, Symbol};
use rustc_span::{sym, Span, DUMMY_SP};
use rustc_span::{sym, BytePos, Span, DUMMY_SP};
use rustc_target::spec::abi;
use rustc_trait_selection::traits::wf::object_region_bounds;
use rustc_trait_selection::traits::{self, NormalizeExt, ObligationCtxt};
@ -1275,8 +1275,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
return;
};
// Get the span of the generics args *including* the leading `::`.
let args_span =
assoc_segment.ident.span.shrink_to_hi().to(args.span_ext);
// We do so by stretching args.span_ext to the left by 2. Earlier
// it was done based on the end of assoc segment but that sometimes
// led to impossible spans and caused issues like #116473
let args_span = args.span_ext.with_lo(args.span_ext.lo() - BytePos(2));
if tcx.generics_of(adt_def.did()).count() == 0 {
// FIXME(estebank): we could also verify that the arguments being
// work for the `enum`, instead of just looking if it takes *any*.