Mark Conditional.execute overrides as @protected

[Shubham-Padkonde]

Description & Motivation

Conditional.execute is already annotated @protected on the base class, but Dart does not propagate that annotation to overrides — each override has to carry it itself. All four Conditional subclasses declared only @override, so the restriction quietly disappeared whenever the caller's static type was the subclass rather than Conditional.

Concretely, on main this code produces no analyzer complaint:

final cond = If(Logic(), then: [Logic() < 1]);
cond.execute(null, null);

final assign = ConditionalAssign(Logic(), Logic());
assign.execute(null, null);

With this change, both calls are flagged:

warning - probe.dart:6:8 - The member 'execute' can only be used within instance members of subclasses of 'If'. - invalid_use_of_protected_member
warning - probe.dart:9:10 - The member 'execute' can only be used within instance members of subclasses of 'ConditionalAssign'. - invalid_use_of_protected_member

Same file analyzed either way: 4 issues without the change, 6 with it — the two new ones being exactly the calls above.

This covers all four subclasses of Conditional (Case, ConditionalAssign, ConditionalGroup, If); I checked for others with grep -rn "extends Conditional\b" lib/src and there are no more.

Related Issue(s)

Fixes #596

Testing

The change is annotation-only, so the analyzer is the real check here.

dart analyze over the whole package is clean:

Analyzing rohd...
No issues found!

That matters because the legitimate internal callers in Combinational and Sequential already carry // ignore: invalid_use_of_protected_member comments — tightening the overrides did not turn any of them into a new warning, and did not require adding any new ignores.

dart format --output=none --set-exit-if-changed reports no changes.

Tests still behave as before — conditionals_test.dart, fsm_test.dart, comb_math_test.dart and comb_mod_test.dart give +31 -25, where all 25 failures are ProcessException ... Command: iverilog -g2012 ... because Icarus Verilog is not installed on my machine, which CONTRIBUTING notes is required for the complete suite. CI has it.

Backwards-compatibility

Not a breaking change for the simulator or generated output — annotations have no runtime effect.

It is a new analyzer warning for any downstream code that was calling execute on a concrete Conditional subclass from outside, which is precisely the misuse #596 asks to surface. Such code was already getting the warning when it went through a Conditional-typed reference, so this makes the existing rule consistent rather than introducing a new one.

Documentation

No documentation changes needed — the base class doc comment on execute already describes it as being called by Always execution, and this just makes the annotations match that.

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Disclosure: this change was written by Claude Code (Claude Opus 5) working as my agent, at my direction. The analyzer output quoted above comes from real runs in my local environment; I am accountable for the content of this PR and happy to iterate on review feedback.

🤖 Generated with Claude Code