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Diffstat (limited to 'crates/hir-ty/src/infer/expr.rs')
| -rw-r--r-- | crates/hir-ty/src/infer/expr.rs | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/crates/hir-ty/src/infer/expr.rs b/crates/hir-ty/src/infer/expr.rs index f307584843..d7c6691ea0 100644 --- a/crates/hir-ty/src/infer/expr.rs +++ b/crates/hir-ty/src/infer/expr.rs @@ -874,9 +874,15 @@ impl<'a> InferenceContext<'a> { }, Expr::Underscore => { // Underscore expressions may only appear in assignee expressions, - // which are handled by `infer_assignee_expr()`, so any underscore - // expression reaching this branch is an error. - self.err_ty() + // which are handled by `infer_assignee_expr()`. + // Any other underscore expression is an error, we render a specialized diagnostic + // to let the user know what type is expected though. + let expected = expected.to_option(&mut self.table).unwrap_or_else(|| self.err_ty()); + self.push_diagnostic(InferenceDiagnostic::TypedHole { + expr: tgt_expr, + expected: expected.clone(), + }); + expected } }; // use a new type variable if we got unknown here @@ -1001,12 +1007,13 @@ impl<'a> InferenceContext<'a> { } &Array::Repeat { initializer, repeat } => { self.infer_expr_coerce(initializer, &Expectation::has_type(elem_ty.clone())); - self.infer_expr( - repeat, - &Expectation::HasType( - TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner), - ), - ); + let usize = TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner); + match self.body[repeat] { + Expr::Underscore => { + self.write_expr_ty(repeat, usize); + } + _ => _ = self.infer_expr(repeat, &Expectation::HasType(usize)), + } ( elem_ty, |