From 6ec81be545eab6a23c164ca045608d9c41b63535 Mon Sep 17 00:00:00 2001
From: David Rubin <sinon@vortan.dev>
Date: Thu, 8 Oct 2026 16:53:48 -0500
Subject: [PATCH] Sema: account for inlined blocks in comptime break

---
 src/Sema.zig         | 41 +++++++++++++++++++++++++++++++----------
 test/behavior/if.zig | 13 +++++++++++++
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/src/Sema.zig b/src/Sema.zig
index 8dda937f375e048096e7b345372c5ae42d2c0b8f..d9c196bb22a14fa1852a81bbf0808998768eaab8 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -17952,19 +17952,40 @@ fn ensurePostHoc(sema: *Sema, block: *Block, dest_block: Zir.Inst.Index) !*Label
 /// break from an inline loop. In such case we must convert it to
 /// a runtime break.
 fn addRuntimeBreak(sema: *Sema, child_block: *Block, block_inst: Zir.Inst.Index, break_operand: Zir.Inst.Ref) !void {
-    const labeled_block = try sema.ensurePostHoc(child_block, block_inst);
-
     const operand = sema.resolveInst(break_operand);
-    const br_ref = try child_block.addBr(labeled_block.label.merges.block_inst, operand);
 
-    try labeled_block.label.merges.results.append(sema.gpa, operand);
-    try labeled_block.label.merges.br_list.append(sema.gpa, br_ref.toIndex().?);
-    try labeled_block.label.merges.src_locs.append(sema.gpa, null);
+    var target_block: ?*Block = child_block;
+    while (target_block) |candidate| : (target_block = candidate.parent) {
+        const label = candidate.label orelse continue;
+        if (label.zir_block != block_inst) continue;
+        switch (sema.code.instructions.items(.tag)[@backingInt(label.zir_block)]) {
+            .block_inline, .block_comptime => continue,
+            else => {},
+        }
+        return sema.addRuntimeBreakToBlock(child_block, candidate, label, operand);
+    }
 
-    labeled_block.block.runtime_index.increment();
-    if (labeled_block.block.runtime_cond == null and labeled_block.block.runtime_loop == null) {
-        labeled_block.block.runtime_cond = child_block.runtime_cond orelse child_block.runtime_loop;
-        labeled_block.block.runtime_loop = child_block.runtime_loop;
+    const labeled_block = try sema.ensurePostHoc(child_block, block_inst);
+    return sema.addRuntimeBreakToBlock(child_block, &labeled_block.block, &labeled_block.label, operand);
+}
+
+fn addRuntimeBreakToBlock(
+    sema: *Sema,
+    child_block: *Block,
+    target_block: *Block,
+    label: *Block.Label,
+    operand: Air.Inst.Ref,
+) !void {
+    const br_ref = try child_block.addBr(label.merges.block_inst, operand);
+
+    try label.merges.results.append(sema.gpa, operand);
+    try label.merges.br_list.append(sema.gpa, br_ref.toIndex().?);
+    try label.merges.src_locs.append(sema.gpa, null);
+
+    target_block.runtime_index.increment();
+    if (target_block.runtime_cond == null and target_block.runtime_loop == null) {
+        target_block.runtime_cond = child_block.runtime_cond orelse child_block.runtime_loop;
+        target_block.runtime_loop = child_block.runtime_loop;
     }
 }
 
diff --git a/test/behavior/if.zig b/test/behavior/if.zig
index 449c6e4c5f4d73e5e1f8e84b4435df11d608da87..3d0d40a334f8b977a278ad68d9eecac9053a353c 100644
--- a/test/behavior/if.zig
+++ b/test/behavior/if.zig
@@ -71,6 +71,19 @@ test "labeled break inside comptime if inside runtime if" {
     try expect(answer == 42);
 }
 
+test "labeled break from comptime block inside runtime if" {
+    var c = true;
+    _ = &c;
+    var reached = false;
+    blk: {
+        if (c) {
+            comptime break :blk;
+        }
+        reached = true;
+    }
+    try expect(!reached);
+}
+
 test "const result loc, runtime if cond, else unreachable" {
     const Num = enum { One, Two };
 
-- 
2.54.0