Function isNarrowableReference

internal/binder/binder.go:2633–2649

(node *ast.Node)

}

func isNarrowableReference(node *ast.Node) bool {
	switch node.Kind {
	case ast.KindIdentifier, ast.KindThisKeyword, ast.KindSuperKeyword, ast.KindMetaProperty:
		return true
	case ast.KindPropertyAccessExpression, ast.KindParenthesizedExpression, ast.KindNonNullExpression:
		return isNarrowableReference(node.Expression())
	case ast.KindElementAccessExpression:
		expr := node.AsElementAccessExpression()
		return ast.IsStringOrNumericLiteralLike(expr.ArgumentExpression) ||
			ast.IsEntityNameExpression(expr.ArgumentExpression) && isNarrowableReference(expr.Expression)
	case ast.KindBinaryExpression:
		expr := node.AsBinaryExpression()
		return expr.OperatorToken.Kind == ast.KindCommaToken && isNarrowableReference(expr.Right) ||
			ast.IsAssignmentOperator(expr.OperatorToken.Kind) && ast.IsLeftHandSideExpression(expr.Left)
	}
	return false
}

func hasNarrowableArgument(expr *ast.Node) bool {
	call := expr.AsCallExpression()