diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_hir_typeck/src/expr.rs | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs index c17aae22ba5..68e096e3bd0 100644 --- a/compiler/rustc_hir_typeck/src/expr.rs +++ b/compiler/rustc_hir_typeck/src/expr.rs @@ -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( |