fix(directive): compile inputs:/outputs: declared in decorator metadata

[ashley-hunter]

Stack (1/4): #493 inputs/outputs → #494 transform validation → #495 queries: → #496 .d.ts transform types. This is #493.

Fixes inputs: and outputs: declared in @Directive / @Component metadata being silently dropped from the compiled definition.

The bug

@Directive({
  selector: 'a',
  inputs: ['x', { name: 'y', alias: 'why', transform: bool }],
})
class A { x?: string; y?: boolean; }

compiled to ɵɵdefineDirective({ type: A, selectors: [["a"]] }): no inputs at all. The decorator parsers never read the inputs/outputs keys, so there was no error either, and a binding like [x]="..." went to the element as a property instead of reaching the directive. The same happened for @Component, for outputs:, and on abstract @Directive() bases (whose subclasses then inherited nothing).

The fix

Both decorator parsers now read inputs: ('name', 'name: alias', { name, alias?, required?, transform? }) and outputs: ('name', 'name: alias') and merge them with @Input/@Output/signal members the way ngtsc does ({...inputsFromMeta, ...inputsFromFields}): keyed by class property, a member replacing a metadata entry in place, a repeated metadata entry keeping its first position, and anything after a second : ignored.

Values are read through directive/evaluator.rs, a single-file model of ngtsc's partial evaluator: literals, template strings, arrays and objects with spreads, and same-file const/let/var. So inputs: [...SHARED, 'x'] with a same-file SHARED resolves like it does in ngtsc. Each file's top-level declarations are only collected when a decorator actually needs one, and each const is evaluated once.

Forms ngtsc rejects now report its diagnostic word for word instead of being dropped: a non-array inputs:/outputs:, entries that aren't strings or object literals, objects without a string name, and a signal input()/output()/model() also listed in the metadata. Like ngtsc, only the first error per class is reported.

Values imported from another file can't be evaluated from one file, so they're reported as unresolvable, where ngtsc would follow the import. Operators and calls in metadata (inputs: cond ? a : b) are also reported rather than evaluated.

Tests

• decorator_inputs_outputs_test.rs: the original report, which failed before the fix.
• decorator_metadata_ngtsc_test.rs compares diagnostics, the inputs/outputs maps and the .d.ts declarations with a snapshot of @angular/compiler-cli 22.1.7's output (tests/fixtures/decorator_metadata_ngtsc.json). The cases are Angular's own specs for decorator inputs/outputs (ngtsc_spec, authoring_{inputs,outputs,models}_spec, the order_bindings compliance case, and the directive_spec acceptance cases), plus probes of the evaluator and its diagnostics. Maps are compared ignoring whitespace and parentheses, which the two emitters place differently.
• The Angular specs are also added to the compare harness (decorator-metadata-angular-spec.fixture.ts), which diffs the full file against a live ngtsc.