try foo() catch (e) { } // legal
try foo() catch e { } // parse error with a migration hint
Same capture style as the for-loop. All four catch shapes keep working
with the parenthesized binding — block, bare-expression body, and the
== match sugar — and the no-binding forms are unchanged. onfail follows
the same rule (onfail (e) { }); its expression-cleanup form is
disambiguated by the paren-group-before-brace lookahead, so
onfail (f()); stays an expression cleanup.
AST unchanged; the printer renders the parens; the #run escape help
text updated. Corpus migrated (57 catch + 3 onfail bindings, in-source
parser test strings, specs incl. grammar rules, readme untouched —
no catch examples there).
Regression: examples/1157-diagnostics-catch-binding-needs-parens.sx;
re-captured stderr for 1010/1013/1037/1123 (migrated source echoed in
carets + help text).
Codex review of 95895a3 found 1051 reached neither lambda arm it claimed to
pin: the lambda arrived only as a var_decl initializer, which routes through
checkCleanupNode's `.var_decl` arm -> cleanupReject(lambda) -> early-return
(a lambda literal is not failable), so the `.lambda` stop never ran; and its
accepted-direction `if !err` guard would still pass with flowExpr's lambda
recursion removed.
Scaffolding-only fix (no compiler change):
- 1051: add a bare lambda STATEMENT `() -> !E { failing(); };` in the cleanup
body so checkCleanupNode sees a `.lambda` node directly and stops (the bare
failable inside is accepted; were the arm to recurse it would reject like
1052). Output byte-identical — only the .sx gained the statement.
- 1053-errors-nested-lambda-liveness-reject (exit 1): an E1.8 value-slot read
inside a never-called nested lambda, rejected only because flowExpr recurses
via `.lambda => analyzeFnBody`. Remove that arm and the diagnostic vanishes
-> suite fails. This is the discriminating negative 1051 lacked.
Gate: zig build test, bash tests/run_examples.sh -> 361/0.
Test-first scaffolding for the path-sensitive error-flow pass
(checkErrorFlow/analyzeFnBody/flowWalk/flowIf/checkCleanupBody) before it
moves into src/ir/error_flow.zig. No compiler change — both examples lock
current behavior.
- 1051-errors-cleanup-closure-boundary (accepted): a closure literal inside a
`defer` body is its own function boundary — the E1.7 cleanup rule and the
parser's try/raise ban both stop at the lambda, and E1.8 value-slot liveness
runs per-boundary. Pins checkCleanupNode's `.lambda` stop + flowExpr's
`.lambda` recursion. Constructible since issue 0073 (0310).
- 1052-errors-cleanup-transitive-reject (exit 1): the E1.7 cleanup check is
transitive — bare failables nested in an `if` (both branches), a nested
block, and a `while` body all reject. Pins checkCleanupNode's recursive arms,
distinct from 1049's direct-body case.
No .test.zig/.ir: diagnostic-pass altitude (checkErrorFlow/A2.4 precedent) —
the pass returns no fact object and emits no IR.
Gate: zig build, zig build test, run_examples.sh -> 360/0.
