Files
sx/examples/errors/1041-errors-failable-closure-shape-union.sx
agra 989e18b760 feat: tuple syntax cutover — Tuple(...) type + .(...) value
Replace the bare-paren tuple grammar with explicit, position-unambiguous
forms, mirroring how structs work:

  type     `(A, B)`        -> `Tuple(A, B)`          (named keeps `:`)
  value    `(a, b)`        -> `.(a, b)`              (named uses `=`)
  typed    (new)           -> `Tuple(A, B).(a, b)`   (like `Point.{...}`)
  failable `-> (T, !)`     -> `-> T !`
           `-> (T1, T2, !)`-> `-> Tuple(T1, T2) !`   (channel outside Tuple)

Bare `(...)` is now grouping only, everywhere; a comma in bare parens is a
hard error with a migration hint. Grouping, function types `(A, B) -> R`,
param lists, lambdas, and match bindings are unaffected.

`Tuple(...)` is strictly a TYPE in every position (including `size_of` /
`type_info` args); a tuple VALUE comes only from `.(...)` (anonymous) or
`Tuple(...).(...)` (explicitly typed). A bare `Tuple(1, 2)` is a tuple
type with non-type elements -> rejected.

The ~110 tuple-bearing corpus files were migrated with a one-shot
AST-aware migrator (the `sx migrate` tool from the prior commit, removed
here). New examples: 0130 (new syntax), 0131 (typed construction), 1060
(named-tuple failable return). 1116 golden updated for the new hint text.
2026-06-25 17:53:57 +03:00

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// Program-wide inferred-`!` union per closure shape (ERR E5.1 sub-feature 2).
// All occurrences of `Closure(i32) -> (i32, !)` share ONE inferred error set;
// every bare-`!` closure literal of that shape unions its raised tags in. A
// `try slot(x)` against any matching-shape slot widens against that union — so
// a caller whose named set covers { Negative, Other } type-checks, and the
// error channel actually carries each closure's own tag at runtime.
#import "modules/std.sx";
All :: error { Negative, Other }
// `h` is a bare-`!` Closure slot; the caller declares the union as `!All`.
dispatch :: (h: Closure(i32) -> i32 !, x: i32) -> i32 !All {
return try h(x);
}
main :: () -> i32 {
gpa := GPA.init();
push Context.{ allocator = xx gpa } {
// Two literals of the SAME shape raising DIFFERENT tags both feed the
// one shared `Closure(i32)->(i32,!)` union node.
handlers : List(Closure(i32) -> i32 !) = .{};
handlers.append(closure((x: i32) -> i32 ! { if x < 0 { raise error.Negative; } return x * 2; }));
handlers.append(closure((x: i32) -> i32 ! { if x == 0 { raise error.Other; } return x + 100; }));
// success paths
print("ok0={}\n", dispatch(handlers.items[0], 5) catch (e) 0); // 10
print("ok1={}\n", dispatch(handlers.items[1], 7) catch (e) 0); // 107
// failure paths: each closure raises its own tag, which propagates
// through `try` and is absorbed by the call-site `catch` fallback
print("err0={}\n", dispatch(handlers.items[0], -1) catch (e) -1); // raised Negative → -1
print("err1={}\n", dispatch(handlers.items[1], 0) catch (e) -2); // raised Other → -2
}
return 0;
}