e44ba4b240
Follow-up #2 from step 2b: pack-fns with a generic return type (`(..\$args) -> \$R`). Today's `monomorphizePackFn` calls `resolveReturnType` which sees `\$R` as a generic name and returns an opaque struct TypeId. The mono's ret_ty is wrong and the value silently coerces to 0. `examples/159-pack-generic-ret.sx` pins this: `first(42)` and `first(99)` both return `0` instead of the call arg. The lock-in captures the wrong output as the snapshot to flip. Next commit infers the ret type from the body's tail expression (arrow form) or the first explicit `return X;` (block form), then builds the mono signature against that concrete type. 198/198 example tests + \`zig build test\` green.
24 lines
790 B
Plaintext
24 lines
790 B
Plaintext
// Variadic heterogeneous type packs — follow-up #2 (generic $R
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// return type).
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//
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// A pack-fn's return type can be a generic name (`$R`) — bound at
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// the call site to match the body's natural type or the caller's
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// target. Today's `monomorphizePackFn` calls `resolveReturnType`
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// which treats `$R` as an opaque struct, so the mono's signature
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// gets a wrong ret_ty and the value is silently zero / garbage.
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//
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// `first(42)` should return 42; the lock-in pins today's `0`.
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// Next commit infers the ret type from the body's tail expression
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// (or first `return X;`) and rebuilds the mono signature.
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#import "modules/std.sx";
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first :: (..$args) -> $R => args[0];
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main :: () -> s32 {
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a : s64 = first(42);
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b : s64 = first(99);
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print("{} {}\n", a, b);
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return 0;
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}
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