/// <summary>
/// Check to see if we have an expression comparing the result of
/// <see cref="System.Linq.Enumerable.Count{TSource}(System.Collections.Generic.IEnumerable{TSource})"/> or
/// <see cref="System.Linq.Enumerable.Count{TSource}(System.Collections.Generic.IEnumerable{TSource}, Func{TSource, bool})"/>
/// using operators.
/// </summary>
private static void AnalyzeBinaryExpression(IBinaryOperation binaryOperation, INamedTypeSymbol enumerableType, Action <Diagnostic> reportDiagnostic)
{
if (binaryOperation.IsComparisonOperator() &&
(IsLeftCountComparison(binaryOperation, enumerableType) || IsRightCountComparison(binaryOperation, enumerableType)))
{
reportDiagnostic(binaryOperation.Syntax.CreateDiagnostic(s_rule));
}
}
protected override PredicateValueKind SetValueForEqualsOrNotEqualsComparisonOperator(IBinaryOperation operation, StringContentAnalysisData negatedCurrentAnalysisData, bool equals)
{
Debug.Assert(operation.IsComparisonOperator());
var predicateValueKind = PredicateValueKind.Unknown;
// Handle 'a == "SomeString"' and 'a != "SomeString"'
SetValueForComparisonOperator(operation.LeftOperand, operation.RightOperand, negatedCurrentAnalysisData, equals, ref predicateValueKind);
// Handle '"SomeString" == a' and '"SomeString" != a'
SetValueForComparisonOperator(operation.RightOperand, operation.LeftOperand, negatedCurrentAnalysisData, equals, ref predicateValueKind);
return(predicateValueKind);
}
protected override PredicateValueKind SetValueForEqualsOrNotEqualsComparisonOperator(IBinaryOperation operation, CopyAnalysisData negatedCurrentAnalysisData, bool equals)
{
Debug.Assert(operation.IsComparisonOperator());
if (GetCopyAbstractValue(operation.LeftOperand).Kind != CopyAbstractValueKind.Unknown &&
GetCopyAbstractValue(operation.RightOperand).Kind != CopyAbstractValueKind.Unknown &&
AnalysisEntityFactory.TryCreate(operation.LeftOperand, out AnalysisEntity leftEntity) &&
AnalysisEntityFactory.TryCreate(operation.RightOperand, out AnalysisEntity rightEntity))
{
var predicateKind = PredicateValueKind.Unknown;
if (!CurrentAnalysisData.TryGetValue(rightEntity, out CopyAbstractValue rightValue))
{
rightValue = new CopyAbstractValue(rightEntity);
}
else if (rightValue.AnalysisEntities.Contains(leftEntity))
{
// We have "a == b && a == b" or "a == b && a != b"
// For both cases, condition on right is always true or always false and redundant.
predicateKind = equals ? PredicateValueKind.AlwaysTrue : PredicateValueKind.AlwaysFalse;
}
else if (negatedCurrentAnalysisData.TryGetValue(rightEntity, out var negatedRightValue) &&
negatedRightValue.AnalysisEntities.Contains(leftEntity))
{
// We have "a == b || a == b" or "a == b || a != b"
// For both cases, condition on right is always true or always false and redundant.
predicateKind = equals ? PredicateValueKind.AlwaysFalse : PredicateValueKind.AlwaysTrue;
}
if (predicateKind != PredicateValueKind.Unknown)
{
if (!equals)
{
// "a == b && a != b" or "a == b || a != b"
// CurrentAnalysisData and negatedCurrentAnalysisData are both unknown values.
foreach (var entity in rightValue.AnalysisEntities)
{
SetAbstractValue(CurrentAnalysisData, entity, CopyAbstractValue.Invalid, fromPredicate: true);
SetAbstractValue(negatedCurrentAnalysisData, entity, CopyAbstractValue.Invalid, fromPredicate: true);
}
}
return(predicateKind);
}
var analysisData = equals ? CurrentAnalysisData : negatedCurrentAnalysisData;
SetAbstractValue(analysisData, leftEntity, rightValue, fromPredicate: true);
}
return(PredicateValueKind.Unknown);
}
protected override PredicateValueKind SetValueForEqualsOrNotEqualsComparisonOperator(IBinaryOperation operation, NullAnalysisData negatedCurrentAnalysisData, bool equals)
{
Debug.Assert(operation.IsComparisonOperator());
var predicateValueKind = PredicateValueKind.Unknown;
// Handle "a == null" and "a != null"
if (SetValueForComparisonOperator(operation.LeftOperand, operation.RightOperand, negatedCurrentAnalysisData, equals, ref predicateValueKind))
{
return(predicateValueKind);
}
// Otherwise, handle "null == a" and "null != a"
SetValueForComparisonOperator(operation.RightOperand, operation.LeftOperand, negatedCurrentAnalysisData, equals, ref predicateValueKind);
return(predicateValueKind);
}
