Grcov report - nil

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//! Regression tests for the three `nil`-coercion bugs closed by

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//! `emit_nil_default` (ADR-0028 Commit A). Before the fix, a `nil` flowing

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//! into a non-`PairRef`, non-`Bool` typed slot (a DO-var sized to a ref/ratio

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//! by its step, a FOLD seed whose accumulator is non-pair, a `nil` literal

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//! passed to a typed closure parameter) emitted an `i32.const 0` `Bool` into

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//! that slot — malformed wasm, or a hard "type mismatch" compile error. Each

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//! test routes a `nil` through `emit_nil_default` and asserts the module

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//! compiles and validates.

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use super::common::compile_and_validate;

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/// Bug 1: a `DO` var with a `nil` init whose step is a pure-native `Ratio`

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/// producer is sized `Ratio`; the `nil` init must seed `push_ratio 0/1`, not

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/// an `i32.const 0`. Runtime loop (`N` is `(entity-count)`).

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#[test]

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fn do_var_nil_init_sized_ratio_by_step() {

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    compile_and_validate(

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        "(let* ((N (entity-count))) \

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           (do ((I 0 (+ I 1)) (ACC nil (transaction-post-date 0))) ((>= I N) ACC)))",

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);

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/// Bug 3: a `FOLD` over a runtime list with a `nil` seed whose accumulator type

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/// probes to `Ratio` (the body returns a ratio). The seed must emit a typed

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/// ratio zero; previously this errored "FOLD: init type Bool doesn't match

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/// accumulator type Ratio".

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#[test]

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fn fold_nil_seed_ratio_accumulator() {

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    compile_and_validate(

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        "(let* ((X (transaction-post-date 0))) \

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           (fold (lambda (acc x) (+ x X)) nil (cons X nil)))",

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);

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/// Bug 2: a runtime closure (captures the runtime `X`) whose parameter unifies

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/// to `Ratio` is invoked with a `nil` literal argument. The `nil` must be

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/// emitted as the parameter's type; previously this errored "closure argument

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/// type mismatch: expected Ratio, got Bool".

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#[test]

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fn closure_call_nil_arg_typed_param() {

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    compile_and_validate(

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        "(let* ((X (transaction-post-date 0)) (F (lambda (A) (if (null? A) X A)))) \

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           (F nil))",

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);

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/// Bug 1, resolved-nil path: a DO var initialized from a SYMBOL bound to `nil`

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/// (a non-literal init that *resolves* to nil) sized `Ratio` by its step. The

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/// resolved-nil branch must emit the typed default, not an `i32.const 0` `Bool`.

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#[test]

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fn do_var_nil_init_via_symbol() {

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    compile_and_validate(

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        "(let* ((N (entity-count)) (Z nil)) \

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           (do ((I 0 (+ I 1)) (ACC Z (transaction-post-date 0))) ((>= I N) ACC)))",

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);

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/// Bug 2, resolved-nil path: a runtime closure invoked with a SYMBOL bound to

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/// `nil`. The coercion must resolve the argument, not just match a literal

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/// `nil`; previously the symbol lowered to `Bool` and hit the type mismatch.

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#[test]

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fn closure_call_symbol_nil_arg() {

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    compile_and_validate(

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        "(let* ((X (transaction-post-date 0)) (Z nil) (F (lambda (A) (if (null? A) X A)))) \

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           (F Z))",

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);

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/// Bug 3, resolved-nil path: a FOLD seed that is a SYMBOL bound to `nil`, with a

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/// `Ratio` accumulator. The resolved-nil seed must emit a typed ratio zero.

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#[test]

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fn fold_symbol_nil_seed_ratio_accumulator() {

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    compile_and_validate(

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        "(let* ((X (transaction-post-date 0)) (Z nil)) \

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           (fold (lambda (acc x) (+ x X)) Z (cons X nil)))",

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);

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/// Bug 3, resolved-nil path with a `PairRef` accumulator: a non-literal nil seed

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/// must route through the resolved-nil branch (which precedes PairRef constant-

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/// list materialization), emitting the empty `$pair` chain after any seed effects.

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#[test]

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fn fold_symbol_nil_seed_pair_accumulator() {

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    compile_and_validate(

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        "(let* ((X (transaction-post-date 0)) (Z nil)) \

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           (fold (lambda (acc x) (cons x acc)) Z (cons X nil)))",

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);

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