private static IfRefactoring CreateIfToReturnWithCoalesceExpression(
IfStatementSyntax ifStatement,
ExpressionSyntax expression1,
ExpressionSyntax expression2,
NullCheckExpression nullCheck,
bool isYield,
SemanticModel semanticModel,
CancellationToken cancellationToken)
{
if (nullCheck.Kind == NullCheckKind.EqualsToNull ||
nullCheck.Kind == NullCheckKind.NotEqualsToNull)
{
if (IsEquivalent(nullCheck.Expression, expression1))
{
return(IfToReturnWithCoalesceExpression.Create(ifStatement, expression1, expression2, isYield));
}
}
if (expression1.IsKind(SyntaxKind.SimpleMemberAccessExpression) &&
SemanticUtilities.IsPropertyOfNullableOfT(expression1, "Value", semanticModel, cancellationToken))
{
expression1 = ((MemberAccessExpressionSyntax)expression1).Expression;
if (IsEquivalent(nullCheck.Expression, expression1))
{
return(IfToReturnWithCoalesceExpression.Create(ifStatement, expression1, expression2, isYield));
}
}
return(null);
}
private static ImmutableArray <IfRefactoring> Analyze(
IfStatementSyntax ifStatement,
ExpressionSyntax condition,
ExpressionSyntax expression1,
ExpressionSyntax expression2,
SemanticModel semanticModel,
CancellationToken cancellationToken,
IfAnalysisOptions options,
bool isYield)
{
if (expression1?.IsMissing == false &&
expression2?.IsMissing == false)
{
if (options.UseCoalesceExpression)
{
SyntaxKind conditionKind = condition.Kind();
if (conditionKind == SyntaxKind.EqualsExpression)
{
var binaryExpression = (BinaryExpressionSyntax)condition;
if (IsNullLiteral(binaryExpression.Right) &&
IsEquivalent(binaryExpression.Left, expression2))
{
return(IfToReturnWithCoalesceExpression.Create(ifStatement, expression2, expression1, isYield).ToImmutableArray());
}
}
else if (conditionKind == SyntaxKind.NotEqualsExpression)
{
var binaryExpression = (BinaryExpressionSyntax)condition;
if (IsNullLiteral(binaryExpression.Right) &&
IsEquivalent(binaryExpression.Left, expression1))
{
return(IfToReturnWithCoalesceExpression.Create(ifStatement, expression1, expression2, isYield).ToImmutableArray());
}
}
}
IfToReturnWithBooleanExpression ifToReturnWithBooleanExpression = null;
if (options.UseBooleanExpression &&
semanticModel.GetTypeSymbol(expression1, cancellationToken)?.IsBoolean() == true &&
semanticModel.GetTypeSymbol(expression2, cancellationToken)?.IsBoolean() == true)
{
ifToReturnWithBooleanExpression = IfToReturnWithBooleanExpression.Create(ifStatement, expression1, expression2, isYield);
}
IfToReturnWithConditionalExpression ifToReturnWithConditionalExpression = null;
if (options.UseConditionalExpression &&
(!expression1.IsBooleanLiteralExpression() || !expression2.IsBooleanLiteralExpression()))
{
ifToReturnWithConditionalExpression = IfToReturnWithConditionalExpression.Create(ifStatement, expression1, expression2, isYield);
}
return(ToImmutableArray(ifToReturnWithBooleanExpression, ifToReturnWithConditionalExpression));
}
return(ImmutableArray <IfRefactoring> .Empty);
}
