private bool NodeMatchesExpression(
SemanticModel originalSemanticModel,
SemanticModel currentSemanticModel,
ISyntaxFactsService syntaxFacts,
TExpressionSyntax expressionInOriginal,
TExpressionSyntax nodeInCurrent,
bool allOccurrences,
CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
if (nodeInCurrent == expressionInOriginal)
{
return(true);
}
else
{
if (allOccurrences &&
this.CanReplace(nodeInCurrent))
{
return(SemanticEquivalence.AreSemanticallyEquivalent(
originalSemanticModel, currentSemanticModel, expressionInOriginal, nodeInCurrent));
}
}
return(false);
}
private bool NodeMatchesExpression(
SemanticModel originalSemanticModel,
SemanticModel currentSemanticModel,
TExpressionSyntax expressionInOriginal,
TExpressionSyntax nodeInCurrent,
bool allOccurrences,
CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
if (nodeInCurrent == expressionInOriginal)
{
return(true);
}
if (allOccurrences && CanReplace(nodeInCurrent))
{
// Original expression and current node being semantically equivalent isn't enough when the original expression
// is a member access via instance reference (either implicit or explicit), the check only ensures that the expression
// and current node are both backed by the same member symbol. So in this case, in addition to SemanticEquivalence check,
// we also check if expression and current node are both instance member access.
//
// For example, even though the first `c` binds to a field and we are introducing a local for it,
// we don't want other references to that field to be replaced as well (i.e. the second `c` in the expression).
//
// class C
// {
// C c;
// void Test()
// {
// var x = [|c|].c;
// }
// }
if (SemanticEquivalence.AreEquivalent(
originalSemanticModel, currentSemanticModel, expressionInOriginal, nodeInCurrent))
{
var originalOperation = originalSemanticModel.GetOperation(expressionInOriginal, cancellationToken);
if (IsInstanceMemberReference(originalOperation))
{
var currentOperation = currentSemanticModel.GetOperation(nodeInCurrent, cancellationToken);
return(IsInstanceMemberReference(currentOperation));
}
// If the original expression is within a static local function, further checks are unnecessary since our scope has already been narrowed down to within the local function.
// If the original expression is not within a static local function, we need to further check whether the expression we're comparing against is within a static local
// function. If so, the expression is not a valid match since we cannot refer to instance variables from within static local functions.
if (!IsExpressionInStaticLocalFunction(expressionInOriginal))
{
return(!IsExpressionInStaticLocalFunction(nodeInCurrent));
}
return(true);
}
}
return(false);