Files
sx/examples/errors/1057-errors-negated-error-binding.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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// `!` on an error binding is the truthiness complement of `if e` (issue
// 0129). Pre-fix, `!` lowered as a bitwise not, so a nonzero error tag
// stayed nonzero and `if !e` held even on a SET error — with the success
// value read as garbage. Integer operands get the same `!x ≡ x == 0`
// semantics.
#import "modules/std.sx";
E :: error { Boom }
f :: (fail: bool) -> i64 !E {
if fail { raise error.Boom; }
return 42;
}
main :: () -> i32 {
// set error: `if e` holds, `if !e` must NOT
v, e := f(true);
took_e := false;
if e { took_e = true; }
if !e { print("BUG: !e held on a set error (v={})\n", v); return 1; }
if !took_e { print("BUG: if e did not hold on a set error\n"); return 2; }
// success: `if !e` holds and the value is real
v2, e2 := f(false);
if e2 { print("BUG: e2 set on success\n"); return 3; }
if !e2 { print("ok: !e2 on success, v2={}\n", v2); }
// integers: `!n` is `n == 0`, not a bit flip
n := 7;
if !n { print("BUG: !7 held\n"); return 4; }
z := 0;
if !z { print("ok: !0 holds\n"); }
print("done\n");
return 0;
}