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).
20 lines
649 B
Plaintext
20 lines
649 B
Plaintext
// Value-carrying `catch` rejection (ERR step E2.1b): when the failable LHS
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// carries a value, a non-diverging catch handler must produce a value of the
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// success type — a value-less (void) body is a type error (otherwise the
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// success and error paths couldn't merge to one value). Diverge instead
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// (`return` / `raise`) or yield a value. Positives: `examples/229-value-failable-consume.sx`.
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#import "modules/std.sx";
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E :: error { Bad }
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parse :: (n: s32) -> (s32, !E) {
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if n < 0 { raise error.Bad; }
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return n;
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}
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main :: () -> s32 {
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x := parse(-1) catch (e) { print("oops\n") }; // error: body yields no value
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return x;
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}
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