| author |  Justus Klausecker <justus@klausecker.de> 2026-01-09 08:04:26+01:00 |
| committer |  Matthew Lugg <mlugg@mlugg.co.uk> 2026-01-11 11:37:17+00:00 |
| log | bce7e7a52ba4dd9b46184925547b40ecedee63b6 |
| tree | 2735a8f54e9f93f498899a2010101b66ab0b97dc |
| parent | 39ca03e5156219c23b3b64d9fa682947ea3b37fa |
| signature |  Commit is signed but in an unrecognized format. |
AstGen: Re-allow labeled `break` from loop `else` block targeting its label
This fixes a regression from a couple of commits ago; breaking from the
`else` block of a loop to the loop's tag should be allowed when explicitly
targeting the label by name.5 files changed, 61 insertions(+), 12 deletions(-)
lib- std
- zig
- test
- cases
lib/std/zig/AstGen.zig+9-11
| ... | ... | @@ -2276,7 +2276,7 @@ fn continueExpr(parent_gz: *GenZir, parent_scope: *Scope, node: Ast.Node.Index) |
| 2276 | 2276 | if (try astgen.tokenIdentEql(label.token, break_label)) { |
| 2277 | 2277 | switch (gen_zir.continue_target) { |
| 2278 | 2278 | .none => { |
| 2279 | return astgen.failNode(node, "continue cannot target labeled block", .{}); | |
| 2279 | return astgen.failNode(node, "continue outside of loop or labeled switch expression", .{}); | |
| 2280 | 2280 | }, |
| 2281 | 2281 | .@"break" => if (opt_rhs != .none) { |
| 2282 | 2282 | return astgen.failNode(node, "cannot continue loop with operand", .{}); |
| ... | ... | @@ -6803,12 +6803,11 @@ fn whileExpr( |
| 6803 | 6803 | break :s &else_scope.base; |
| 6804 | 6804 | } |
| 6805 | 6805 | }; |
| 6806 | // Remove label and forbid unlabeled control flow to this scope so that | |
| 6807 | // `continue` and `break` control flow apply to outer loops; not this one. | |
| 6808 | loop_scope.label = null; | |
| 6806 | // Disallow unlabeled control flow to this scope so that bare `continue` | |
| 6807 | // and `break` control flow apply to outer loops; not this one. | |
| 6808 | // Also disallow `continue` targeting the loop label. | |
| 6809 | 6809 | loop_scope.allow_unlabeled_control_flow = false; |
| 6810 | loop_scope.continue_target = undefined; | |
| 6811 | loop_scope.break_target = undefined; | |
| 6810 | loop_scope.continue_target = .none; | |
| 6812 | 6811 | const else_result = try fullBodyExpr(&else_scope, sub_scope, loop_scope.break_result_info, else_node, .allow_branch_hint); |
| 6813 | 6812 | if (is_statement) { |
| 6814 | 6813 | _ = try addEnsureResult(&else_scope, else_result, else_node); |
| ... | ... | @@ -7093,12 +7092,11 @@ fn forExpr( |
| 7093 | 7092 | |
| 7094 | 7093 | if (for_full.ast.else_expr.unwrap()) |else_node| { |
| 7095 | 7094 | const sub_scope = &else_scope.base; |
| 7096 | // Remove label and forbid unlabeled control flow to this scope so that | |
| 7097 | // `continue` and `break` control flow apply to outer loops; not this one. | |
| 7098 | loop_scope.label = null; | |
| 7095 | // Disallow unlabeled control flow to this scope so that bare `continue` | |
| 7096 | // and `break` control flow apply to outer loops; not this one. | |
| 7097 | // Also disallow `continue` targeting the loop label. | |
| 7099 | 7098 | loop_scope.allow_unlabeled_control_flow = false; |
| 7100 | loop_scope.continue_target = undefined; | |
| 7101 | loop_scope.break_target = undefined; | |
| 7099 | loop_scope.continue_target = .none; | |
| 7102 | 7100 | const else_result = try fullBodyExpr(&else_scope, sub_scope, loop_scope.break_result_info, else_node, .allow_branch_hint); |
| 7103 | 7101 | if (is_statement) { |
| 7104 | 7102 | _ = try addEnsureResult(&else_scope, else_result, else_node); |
test/behavior/for.zig+17
| ... | ... | @@ -524,3 +524,20 @@ test "for loop 0 length range" { |
| 524 | 524 | comptime unreachable; |
| 525 | 525 | } |
| 526 | 526 | } |
| 527 | ||
| 528 | test "labeled break from else prong" { | |
| 529 | const S = struct { | |
| 530 | fn doTheTest(x: u32) !void { | |
| 531 | var y: u32 = 0; | |
| 532 | const ok = label: while (y < x) : (y += 1) { | |
| 533 | if (y == 10) break :label false; | |
| 534 | } else { | |
| 535 | break :label true; | |
| 536 | }; | |
| 537 | try expect(ok); | |
| 538 | } | |
| 539 | }; | |
| 540 | ||
| 541 | try S.doTheTest(5); | |
| 542 | try comptime S.doTheTest(5); | |
| 543 | } |
test/behavior/while.zig+17
| ... | ... | @@ -399,3 +399,20 @@ test "breaking from a loop in an if statement" { |
| 399 | 399 | } else 2; |
| 400 | 400 | _ = opt; |
| 401 | 401 | } |
| 402 | ||
| 403 | test "labeled break from else prong" { | |
| 404 | const S = struct { | |
| 405 | fn doTheTest(x: u32) !void { | |
| 406 | var y: u32 = 0; | |
| 407 | const ok = label: while (y < x) : (y += 1) { | |
| 408 | if (y == 10) break :label false; | |
| 409 | } else { | |
| 410 | break :label true; | |
| 411 | }; | |
| 412 | try expect(ok); | |
| 413 | } | |
| 414 | }; | |
| 415 | ||
| 416 | try S.doTheTest(5); | |
| 417 | try comptime S.doTheTest(5); | |
| 418 | } |
test/cases/compile_errors/continue_loop_from_else_block.zig created+17
| ... | ... | @@ -0,0 +1,17 @@ |
| 1 | export fn entry1() void { | |
| 2 | var x: u32 = 0; | |
| 3 | result: while (x < 5) : (x += 1) {} else { | |
| 4 | continue :result; | |
| 5 | } | |
| 6 | } | |
| 7 | ||
| 8 | export fn entry2() void { | |
| 9 | result: for (0..5) |_| {} else { | |
| 10 | continue :result; | |
| 11 | } | |
| 12 | } | |
| 13 | ||
| 14 | // error | |
| 15 | // | |
| 16 | // :4:9: error: continue outside of loop or labeled switch expression | |
| 17 | // :10:9: error: continue outside of loop or labeled switch expression |
test/cases/compile_errors/labeled_block_continue.zig+1-1
| ... | ... | @@ -7,4 +7,4 @@ export fn foo() void { |
| 7 | 7 | |
| 8 | 8 | // error |
| 9 | 9 | // |
| 10 | // :3:9: error: continue cannot target labeled block | |
| 10 | // :3:9: error: continue outside of loop or labeled switch expression |