From 20487a1b4a7c2fdffdb1de61c7837ee6f673f21a Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Thu, 3 Jun 2021 23:12:35 +0200
Subject: Fix coercion in match with expected type

Plus add infrastructure to test type mismatches without expect.
---
 crates/hir_ty/src/infer/expr.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'crates/hir_ty/src/infer')

diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index f73bf43b2..e34f194ff 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -337,10 +337,15 @@ impl<'a> InferenceContext<'a> {
             Expr::Match { expr, arms } => {
                 let input_ty = self.infer_expr(*expr, &Expectation::none());
 
+                let expected = expected.adjust_for_branches(&mut self.table);
+
                 let mut result_ty = if arms.is_empty() {
                     TyKind::Never.intern(&Interner)
                 } else {
-                    self.table.new_type_var()
+                    match &expected {
+                        Expectation::HasType(ty) => ty.clone(),
+                        _ => self.table.new_type_var(),
+                    }
                 };
 
                 let matchee_diverges = self.diverges;
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