AstGen: coerce break operands of labeled blocks

Similar code was already in place for conditional branches. This updates
AstGen to do the same for labeled blocks. It takes advantage of the
`store_to_block_ptr` instructions by mutating them in place to become
`as` instructions, coercing the break operands before they are returned
from the block.

1 files changed, 12 insertions, 0 deletions

diff --git a/test/behavior/basic.zig b/test/behavior/basic.zig
index 6c21b8dd6c..134ca1a235 100644
--- a/test/behavior/basic.zig
+++ b/test/behavior/basic.zig
@@ -875,3 +875,15 @@ test "catch in block has correct result location" {
     };
     try expect(config_h_text == 1);
 }
+
+test "labeled block with runtime branch forwards its result location type to break statements" {
+    const E = enum { a, b };
+    var a = false;
+    const e: E = blk: {
+        if (a) {
+            break :blk .a;
+        }
+        break :blk .b;
+    };
+    try expect(e == .b);
+}