83ec2536af
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).
21 lines
932 B
Plaintext
21 lines
932 B
Plaintext
// A closure literal whose body `raise`s but is annotated non-failable (or has
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// no `!` in its return) gets a LAMBDA-SPECIFIC diagnostic telling the user to
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// declare the failable return explicitly (ERR E5.1 sub-feature 1). This is the
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// closure analog of the top-level "raise is only valid inside a failable
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// function" error — failability is never inferred for a lambda, it must be
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// declared, so a raising lambda with no `!` is a hard error pointing at the fix.
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#import "modules/std.sx";
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E :: error { Neg }
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take :: (cb: Closure(s32) -> (s32, !E), x: s32) -> s32 { return cb(x) catch (e) -1; }
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main :: () -> s32 {
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// `-> s32` (non-failable) but the body raises → lambda-specific hint:
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// "lambda body raises; declare its return type explicitly with
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// `-> (T, !)` or `-> (T, !Named)`"
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print("{}\n", take(closure((x: s32) -> s32 { if x < 0 { raise error.Neg; } return x; }), -1));
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return 0;
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}
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