Method insert

crates/ruff_python_parser/src/semantic_errors.rs:2335–2347

Add an identifier to the set of visited names in `self` and emit a [`SemanticSyntaxError`] if `ident` has already been seen.

(&mut self, ident: &'a ast::Identifier)

    /// Add an identifier to the set of visited names in `self` and emit a [`SemanticSyntaxError`]
    /// if `ident` has already been seen.
    fn insert(&mut self, ident: &'a ast::Identifier) {
        if !self.names.insert(&ident.id) {
            SemanticSyntaxChecker::add_error(
                self.ctx,
                SemanticSyntaxErrorKind::MultipleCaseAssignment(ident.id.clone()),
                ident.range(),
            );
        }
        // test_err debug_shadow_match
        // match x:
        //     case __debug__: ...
        SemanticSyntaxChecker::check_identifier(ident, self.ctx);
    }
}

struct InvalidExpressionVisitor<'a, Ctx> {