[syntax-errors] Reimplement `break-outside-loop` (`F701`) as a semantic syntax error by 11happy · Pull Request #20556 · astral-sh/ruff

11happy · 2025-09-24T16:52:30Z

Summary

This PR implements https://docs.astral.sh/ruff/rules/break-outside-loop/ (F701) as a semantic syntax error.

Test Plan

ntBre · 2025-09-24T17:15:42Z

crates/ruff_python_parser/src/semantic_errors.rs

+                    inside_orelse: false,
+                });
+                for stmt in body {
+                    self.visit_stmt(stmt, ctx);


We shouldn't be recursing here. The SemanticSyntaxChecker isn't a full Visitor, it only checks the single Stmt it's given and relies on the parent visitor (either Checker in Ruff or SemanticIndexBuilder in ty) to drive the AST traversal.

I think this also means that managing the loop state isn't really feasible in the SemanticSyntaxChecker itself. Instead, we'll probably need to add in_loop_context as a method on the SemanticSyntaxContext trait and implement it for Ruff and ty (and the test visitor if we want to write inline tests).

You could also consider trying to add a SemanticSyntaxContext::current_statements() method, which would be more general and match how Ruff currently implements this check:

ruff/crates/ruff_linter/src/checkers/ast/analyze/statement.rs

Lines 54 to 61 in 83f80ef

if checker.is_rule_enabled(Rule::BreakOutsideLoop) {

pyflakes::rules::break_outside_loop(

checker,

stmt,

&mut checker.semantic.current_statements().skip(1),

);

}

}

Those are just some ideas based on a quick look, hope that helps!

Sure, Thank you for these pointers, I will try them out & keep you updated : )

done, I have added a new current_statements .

Thank you : )

Signed-off-by: 11happy <[email protected]>

github-actions · 2025-10-05T13:07:47Z

Diagnostic diff on typing conformance tests

No changes detected when running ty on typing conformance tests ✅

github-actions · 2025-10-05T13:08:31Z

`mypy_primer` results

No ecosystem changes detected ✅
No memory usage changes detected ✅

Signed-off-by: 11happy <[email protected]>

github-actions · 2025-10-05T13:28:12Z

`ruff-ecosystem` results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

ntBre

Thanks! But I think we can make a few improvements here.

ntBre · 2025-10-06T19:26:48Z

crates/ruff_linter/src/rules/pyflakes/mod.rs

I don't think we should delete this test case. We still need to emit F701, even if the main implementation is as a syntax error.

ntBre · 2025-10-06T19:27:20Z

crates/ty_python_semantic/src/semantic_index/builder.rs

            self.semantic_syntax_errors.borrow_mut().push(error);
        }
    }
+    fn in_loop_context(&self) -> bool {


Suggested change

fn in_loop_context(&self) -> bool {

fn in_loop_context(&self) -> bool {

ntBre · 2025-10-06T19:27:37Z

crates/ruff_python_parser/src/semantic_errors.rs

                    self.seen_futures_boundary = true;
                }
            }
+


Suggested change

ntBre · 2025-10-06T19:30:13Z

crates/ruff_linter/src/checkers/ast/mod.rs

    }
+
+    fn in_loop_context(&self) -> bool {
+        let statements = self.current_statements();


I don't think we need to track a separate Vec of current statements on the Checker. This should already be available on the SemanticModel field, as in the code I linked earlier.

Suggested change

let statements = self.current_statements();

let statements = self.semantic.current_statements();

My earlier suggestion about adding a current_statements method was not for Checker, I meant that instead of SemanticSyntaxContext::in_loop_context, we could consider adding SemanticSyntaxContext::current_statements, which would return an iterator over Stmt nodes:

fn current_statements(&self) -> impl Iterator<Item = &Stmt> { self.semantic.current_statements() }

This should be easier to implement for both Ruff and ty, and then the actual in_loop_context check could be shared between the two. But I think SemanticSyntaxContext::in_loop_context is also okay, especially if you tried this already.

ntBre · 2025-10-06T19:32:00Z

crates/ruff_linter/src/checkers/ast/mod.rs

+            match *parent {
+                Stmt::For(ast::StmtFor { orelse, .. })
+                | Stmt::While(ast::StmtWhile { orelse, .. }) => {
+                    let in_orelse = orelse.contains(cur_stmt.unwrap());


I think we should just pass the current statement in, like in the original F701 implementation, to avoid needing to unwrap here.

Signed-off-by: 11happy <[email protected]>

ntBre

Thank you! I pushed a couple of very small cleanups, but this looks good to me now.

…tity * origin/main: (24 commits) Update Python compatibility from 3.13 to 3.14 in README.md (#20852) [syntax-errors]: break outside loop F701 (#20556) [ty] Treat `Callable`s as bound-method descriptors in special cases (#20802) [ty] Do not bind self to non-positional parameters (#20850) Fix syntax error false positives on parenthesized context managers (#20846) [ty] Remove 'pre-release software' warning (#20817) Render unsupported syntax errors in formatter tests (#20777) [ty] Treat functions, methods, and dynamic types as function-like `Callable`s (#20842) [ty] Move logic for `super()` inference to a new `types::bound_super` submodule (#20840) [ty] Fix false-positive diagnostics on `super()` calls (#20814) [ty] Move `class_member` to `member` module (#20837) [`ruff`] Use DiagnosticTag for more flake8 and numpy rules (#20758) [ty] Prefer declared base class attribute over inferred attribute on subclass (#20764) [ty] Log files that are slow to type check (#20836) Update cargo-bins/cargo-binstall action to v1.15.7 (#20827) Update CodSpeedHQ/action action to v4.1.1 (#20828) Update Rust crate pyproject-toml to v0.13.7 (#20835) Update Rust crate anstream to v0.6.21 (#20829) Update Rust crate libc to v0.2.177 (#20832) Update Rust crate memchr to v2.7.6 (#20834) ...

* main: (25 commits) [ty] Diagnostic for generic classes that reference typevars in enclosing scope (#20822) Update Python compatibility from 3.13 to 3.14 in README.md (#20852) [syntax-errors]: break outside loop F701 (#20556) [ty] Treat `Callable`s as bound-method descriptors in special cases (#20802) [ty] Do not bind self to non-positional parameters (#20850) Fix syntax error false positives on parenthesized context managers (#20846) [ty] Remove 'pre-release software' warning (#20817) Render unsupported syntax errors in formatter tests (#20777) [ty] Treat functions, methods, and dynamic types as function-like `Callable`s (#20842) [ty] Move logic for `super()` inference to a new `types::bound_super` submodule (#20840) [ty] Fix false-positive diagnostics on `super()` calls (#20814) [ty] Move `class_member` to `member` module (#20837) [`ruff`] Use DiagnosticTag for more flake8 and numpy rules (#20758) [ty] Prefer declared base class attribute over inferred attribute on subclass (#20764) [ty] Log files that are slow to type check (#20836) Update cargo-bins/cargo-binstall action to v1.15.7 (#20827) Update CodSpeedHQ/action action to v4.1.1 (#20828) Update Rust crate pyproject-toml to v0.13.7 (#20835) Update Rust crate anstream to v0.6.21 (#20829) Update Rust crate libc to v0.2.177 (#20832) ...

…rable * origin/main: (26 commits) [ty] Add separate type for typevar "identity" (#20813) [ty] Diagnostic for generic classes that reference typevars in enclosing scope (#20822) Update Python compatibility from 3.13 to 3.14 in README.md (#20852) [syntax-errors]: break outside loop F701 (#20556) [ty] Treat `Callable`s as bound-method descriptors in special cases (#20802) [ty] Do not bind self to non-positional parameters (#20850) Fix syntax error false positives on parenthesized context managers (#20846) [ty] Remove 'pre-release software' warning (#20817) Render unsupported syntax errors in formatter tests (#20777) [ty] Treat functions, methods, and dynamic types as function-like `Callable`s (#20842) [ty] Move logic for `super()` inference to a new `types::bound_super` submodule (#20840) [ty] Fix false-positive diagnostics on `super()` calls (#20814) [ty] Move `class_member` to `member` module (#20837) [`ruff`] Use DiagnosticTag for more flake8 and numpy rules (#20758) [ty] Prefer declared base class attribute over inferred attribute on subclass (#20764) [ty] Log files that are slow to type check (#20836) Update cargo-bins/cargo-binstall action to v1.15.7 (#20827) Update CodSpeedHQ/action action to v4.1.1 (#20828) Update Rust crate pyproject-toml to v0.13.7 (#20835) Update Rust crate anstream to v0.6.21 (#20829) ...

11happy mentioned this pull request Sep 24, 2025

[syntax-errors] Remaining syntax errors raised by the compiler #17412

Open

14 tasks

ntBre reviewed Sep 24, 2025

View reviewed changes

11happy added 3 commits October 5, 2025 18:35

feat: draft implementation for break outside loop

07b217c

Signed-off-by: 11happy <[email protected]>

refactor: add current_statement in checker

050fc32

Signed-off-by: 11happy <[email protected]>

chore: clean up

131cd06

Signed-off-by: 11happy <[email protected]>

11happy force-pushed the F701 branch from 2050b6c to 131cd06 Compare October 5, 2025 13:05

chore: remove previous snap

13a3021

Signed-off-by: 11happy <[email protected]>

11happy marked this pull request as ready for review October 5, 2025 13:21

11happy requested review from AlexWaygood, MichaReiser, carljm, dcreager, dhruvmanila and sharkdp as code owners October 5, 2025 13:21

ntBre requested changes Oct 6, 2025

View reviewed changes

11happy and others added 8 commits October 11, 2025 21:13

feat: correct implementation

c6e1c0f

Signed-off-by: 11happy <[email protected]>

test: re-enable F701

3172076

Signed-off-by: 11happy <[email protected]>

chore: fix space

1d88862

Signed-off-by: 11happy <[email protected]>

chore: remove unreferenced snapshot

69d8dc3

Signed-off-by: 11happy <[email protected]>

revert a few whitespace changes

dfb6e0a

move comment with function check

7289845

cur_stmt -> child

f6eac23

fix missing rule code comments

88f4b6f

ntBre approved these changes Oct 13, 2025

View reviewed changes

ntBre enabled auto-merge (squash) October 13, 2025 19:57

ntBre added the internal An internal refactor or improvement label Oct 13, 2025

ntBre changed the title ~~[syntax-errors]: break outside loop F701~~ [syntax-errors]: Reimplement break-outside-loop (F701) as a semantic syntax error Oct 13, 2025

ntBre changed the title ~~[syntax-errors]: Reimplement break-outside-loop (F701) as a semantic syntax error~~ [syntax-errors] Reimplement break-outside-loop (F701) as a semantic syntax error Oct 13, 2025

ntBre merged commit 2b729b4 into astral-sh:main Oct 13, 2025
41 checks passed

	if checker.is_rule_enabled(Rule::BreakOutsideLoop) {
	pyflakes::rules::break_outside_loop(
	checker,
	stmt,
	&mut checker.semantic.current_statements().skip(1),
	);
	}
	}

	fn in_loop_context(&self) -> bool {

	fn in_loop_context(&self) -> bool {

	let statements = self.current_statements();
	let statements = self.semantic.current_statements();

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11happy commented Sep 24, 2025

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