public static IEnumerable<ReplaceAction> GetSimplifications(ConditionalExpressionSyntax ternaryNode, ISemanticModel model, Assumptions assume, CancellationToken cancellationToken = default(CancellationToken))
{
if (!ternaryNode.DefinitelyHasBooleanType(model)) yield break;
var whenTrueFalseCmp = ternaryNode.WhenTrue.TryEvalAlternativeComparison(ternaryNode.WhenFalse, model, assume);
if (whenTrueFalseCmp == true) {
// (c ? b : b) --> b
yield return new ReplaceAction(
"Simplify",
ternaryNode,
ternaryNode.WhenTrue);
// if condition has side effects we may need to keep it
// (c ? b : b) --> ((c && false) || b)
if (ternaryNode.Condition.HasSideEffects(model, assume) != false) {
var replacement = ternaryNode.Condition
.BracketedOrProtected()
.BOpLogicalAnd(false.AsLiteral())
.Bracketed()
.BOpLogicalOr(ternaryNode.WhenTrue);
yield return new ReplaceAction(
"Simplify (keeping condition evaluation)",
ternaryNode,
replacement);
}
}
if (whenTrueFalseCmp == false) {
// (c ? b : !b) --> (c == b)
var replacement = ternaryNode.Condition
.BracketedOrProtected()
.BOpEquals(ternaryNode.WhenTrue);
yield return new ReplaceAction(
"Simplify",
ternaryNode,
replacement);
}
}
