AstGen: fix `dbg_block_end` being inserted before last instruction in block

Closes #14125

1 files changed, 8 insertions, 2 deletions

diff --git a/src/AstGen.zig b/src/AstGen.zig
index e70424188a..91dea526dc 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -6942,7 +6942,13 @@ fn switchExpr(
                 // it as the break operand.
                 if (body_len < 2)
                     break :blk;
-                const store_inst = payloads.items[end_index - 2];
+
+                var store_index = end_index - 2;
+                while (true) : (store_index -= 1) switch (zir_tags[payloads.items[store_index]]) {
+                    .dbg_block_end, .dbg_block_begin, .dbg_stmt, .dbg_var_val, .dbg_var_ptr => {},
+                    else => break,
+                };
+                const store_inst = payloads.items[store_index];
                 if (zir_tags[store_inst] != .store_to_block_ptr or
                     zir_datas[store_inst].bin.lhs != block_scope.rl_ptr)
                     break :blk;
@@ -12150,7 +12156,7 @@ const GenZir = struct {
 
         const new_index = @intCast(Zir.Inst.Index, gz.astgen.instructions.len);
         try gz.astgen.instructions.append(gpa, .{ .tag = .dbg_block_end, .data = undefined });
-        try gz.instructions.insert(gpa, gz.instructions.items.len - 1, new_index);
+        try gz.instructions.append(gpa, new_index);
     }
 };