bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Rollup merge of #110096 - compiler-errors:tweak-tuple-idx-msg, r=Nilstrieb

Browse source 
Tweak tuple indexing suggestion

Fixes #110091
This commit is contained in:
Yuki Okushi 2023-04-09 12:35:56 +09:00 • committed by GitHub
commit eed27ac7f4
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
5 changed files with 35 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

29
compiler/rustc_hir_typeck/src/expr.rs
View file

@ -2810,23 +2810,26 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
"cannot index into a value of type `{base_t}`",
);
// Try to give some advice about indexing tuples.
if let ty::Tuple(..) = base_t.kind() {
if let ty::Tuple(types) = base_t.kind() {
let mut needs_note = true;
// If the index is an integer, we can show the actual
// fixed expression:
if let ExprKind::Lit(ref lit) = idx.kind {
if let ast::LitKind::Int(i, ast::LitIntType::Unsuffixed) = lit.node {
let snip = self.tcx.sess.source_map().span_to_snippet(base.span);
if let Ok(snip) = snip {
err.span_suggestion(
expr.span,
"to access tuple elements, use",
format!("{snip}.{i}"),
Applicability::MachineApplicable,
);
needs_note = false;
}
if let ExprKind::Lit(ref lit) = idx.kind
&& let ast::LitKind::Int(i, ast::LitIntType::Unsuffixed) = lit.node
&& i < types.len().try_into().expect("expected tuple index to be < usize length")
{
let snip = self.tcx.sess.source_map().span_to_snippet(base.span);
if let Ok(snip) = snip {
err.span_suggestion(
expr.span,
"to access tuple elements, use",
format!("{snip}.{i}"),
Applicability::MachineApplicable,
);
needs_note = false;
}
} else if let ExprKind::Path(..) = idx.peel_borrows().kind {
err.span_label(idx.span, "cannot access tuple elements at a variable index");
}
if needs_note {
err.help(