2e6e031233
A closure VALUE (a pre-bound variable) flowing into a bare (T)->U slot was passed unsoundly: the bare ABI calls fn_ptr(ctx, args) with no env channel, so the closure's underlying fn (which takes an env slot) had its env dropped and args shifted — UB for a matching ABI, a wrong-tuple read for the non-failable->failable widening (returned -1), and a segfault when the closure captured. coerceToType now rejects a .closure -> .function coercion with a diagnostic pointing at the idiom (pass the literal directly, which gets the static adapter, or type the parameter Closure(...) so the env is carried). Closure LITERALS are unaffected — lowerLambda pre-adapts them to a .function-typed value before coercion. Regression: 1045-errors-closure-var-bare-slot-reject.sx.
28 lines
1.2 KiB
Plaintext
28 lines
1.2 KiB
Plaintext
// A closure VALUE (a pre-bound variable) cannot be passed into a bare
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// function-pointer slot `(...) -> ...` (ERR E5.1). The bare ABI calls
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// `fn_ptr(ctx, args)` with no env channel, so a closure's environment can't be
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// carried — passing one is unsound (drops env / shifts args / segfaults on a
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// capturing closure). Only a closure LITERAL crosses this boundary (lowerLambda
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// emits a static adapter); a variable is rejected with a pointer to the idiom.
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//
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// The fix for these is either to pass the literal directly, or to type the
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// parameter `Closure(...)` so the environment is carried (the idiomatic form).
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#import "modules/std.sx";
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E :: error { Z }
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bare :: (cb: (s64) -> s64, n: s64) -> s64 { return cb(n); }
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baref :: (cb: (s64) -> (s64, !E), n: s64) -> s64 { return cb(n) catch e -1; }
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main :: () -> s32 {
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inc := closure((x: s64) -> s64 => x + 1); // capture-free closure var
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base := 100;
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add := closure((x: s64) -> s64 => x + base); // CAPTURING closure var
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_ := bare(inc, 9); // reject: closure value → bare slot
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_ := baref(inc, 9); // reject: also the ∅-widening crossing
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_ := bare(add, 9); // reject: capturing closure → bare slot
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return 0;
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}
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