From 8fa88c88c28420d89392a9984748070d35f18321 Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Sun, 5 Jun 2022 20:08:02 +0300
Subject: [PATCH] AstGen: fix coercion scope type when stores are eliminated

---
 src/AstGen.zig          |  3 +++
 test/behavior/basic.zig | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/AstGen.zig b/src/AstGen.zig
index ab5befa4ba..2fa2960ce1 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -9875,6 +9875,9 @@ const GenZir = struct {
         errdefer as_scope.unstack();
         as_scope.rl_ptr = try as_scope.addBin(.coerce_result_ptr, dest_type, result_ptr);
 
+        // `rl_ty_inst` needs to be set in case the stores to `rl_ptr` are eliminated.
+        as_scope.rl_ty_inst = dest_type;
+
         return as_scope;
     }
 
diff --git a/test/behavior/basic.zig b/test/behavior/basic.zig
index b45f5a0b49..dc0e5aaf30 100644
--- a/test/behavior/basic.zig
+++ b/test/behavior/basic.zig
@@ -1062,3 +1062,15 @@ comptime {
     s = S{ .a = 1 };
     assert(s.a == 1);
 }
+
+test "switch inside @as gets correct type" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+
+    var a: u32 = 0;
+    var b: [2]u32 = undefined;
+    b[0] = @as(u32, switch (a) {
+        1 => 1,
+        else => 0,
+    });
+}