private bool CanIntroduceVariable(
bool isSpanEmpty,
CancellationToken cancellationToken)
{
if (!_service.CanIntroduceVariableFor(this.Expression))
{
return(false);
}
if (isSpanEmpty && this.Expression is TNameSyntax)
{
// to extract a name, you must have a selection (this avoids making the refactoring too noisy)
return(false);
}
if (this.Expression is TTypeSyntax && !(this.Expression is TNameSyntax))
{
// name syntax can introduce variables, but not other type syntaxes
return(false);
}
// Even though we're creating a variable, we still ask if we can be replaced with an
// RValue and not an LValue. This is because introduction of a local adds a *new* LValue
// location, and we want to ensure that any writes will still happen to the *original*
// LValue location. i.e. if you have: "a[1] = b" then you don't want to change that to
// "var c = a[1]; c = b", as that write is no longer happening into the right LValue.
//
// In essence, this says "i can be replaced with an expression as long as I'm not being
// written to".
var semanticFacts = this.Document.Project.LanguageServices.GetService <ISemanticFactsService>();
return(semanticFacts.CanReplaceWithRValue(this.Document.SemanticModel, this.Expression, cancellationToken));
}
private bool CanIntroduceVariable(
CancellationToken cancellationToken)
{
// Don't generate a variable for an expression that's the only expression in a
// statement. Otherwise we'll end up with something like "v;" which is not
// legal in C#.
if (!_service.CanIntroduceVariableFor(this.Expression))
{
return(false);
}
if (this.Expression is TTypeSyntax)
{
return(false);
}
// Even though we're creating a variable, we still ask if we can be replaced with an
// RValue and not an LValue. This is because introduction of a local adds a *new* LValue
// location, and we want to ensure that any writes will still happen to the *original*
// LValue location. i.e. if you have: "a[1] = b" then you don't want to change that to
// "var c = a[1]; c = b", as that write is no longer happening into the right LValue.
//
// In essense, this says "i can be replaced with an expression as long as i'm not being
// written to".
var semanticFacts = this.Document.Project.LanguageServices.GetService <ISemanticFactsService>();
return(semanticFacts.CanReplaceWithRValue(this.Document.SemanticModel, this.Expression, cancellationToken));
}