[red-knot] Literal[True,False] normalized to builtins.bool

[dylwil3]

The UnionBuilder builds builtins.bool when handed Literal[True] and Literal[False].

Caveat: If the builtins module is unfindable somehow, the builder falls back to the union type of these two literals.

First task from #12694

[dylwil3]

Note: Attempting to call builtins_symbol_ty_by_name on a the default TestDb (without making a src directory and initializing a Program) causes a panic. Is this expected behavior? From the docstring I would've expected to just get Type::Unbound. The panic originates from Program::get(db) here:

ruff/crates/red_knot_python_semantic/src/module_resolver/resolver.rs

Lines 545 to 550 in 3ceedf7

	/// Given a module name and a list of search paths in which to lookup modules,
	/// attempt to resolve the module name
	fn resolve_name(db: &dyn Db, name: &ModuleName) -> Option<(SearchPath, File, ModuleKind)> {
	let program = Program::get(db);
	let target_version = program.target_version(db);
	let resolver_state = ResolverContext::new(db, target_version);

If that's unexpected I can open an issue.

[github-actions]

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[carljm]

Thank you!!

It's not great that we can create a TestDb without a Program which will then panic in some cases; it'd be ideal if creating a TestDb always created a fully functional db, or if the lack of a Program were handled more gracefully than a panic. Thanks for catching that! I can create an issue for it later; should be addressed separately.

[carljm]

Looks great!

[carljm]

nice approach!

[MichaReiser]

It would be interesting to look at the generated code. into creates an OrderSet which in turn allocates.

I prefer using self.elements.contains(Type::BooleanLiteral(true) && self.elements.contains(Type::BooleanLiteral(false)), which does not depend on the compiler being able to see through that the allocation isn't necessary (which requires rather involved analysis)