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Merged
brettfo merged 1 commit into from
Mar 19, 2015
Merged

null check a token's parent to prevent a NullReferenceException #1234

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56 changes: 23 additions & 33 deletions ...orFeatures/Core/Implementation/IntelliSense/SignatureHelp/CommonSignatureHelpUtilities.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -113,46 +113,36 @@ internal static bool TryGetSyntax<TSyntax>(
out TSyntax expression)
where TSyntax : SyntaxNode
{
// Bug 1100661 reports an NRE from this method, but no manual repro has been found. To aid in debugging,
// any NRE thrown from here will generate a dump via FatalError.Report() below. try/catch was added 1/2/2015
// and is expected to be removed by 4/1/2015. --brettfo
try
var token = syntaxFacts.FindTokenOnLeftOfPosition(root, position);
if (triggerReason == SignatureHelpTriggerReason.TypeCharCommand)
{
var token = syntaxFacts.FindTokenOnLeftOfPosition(root, position);
if (triggerReason == SignatureHelpTriggerReason.TypeCharCommand)
if (isTriggerToken(token))
{
if (isTriggerToken(token))
{
expression = token.GetAncestor<TSyntax>();
return true;
}
expression = token.GetAncestor<TSyntax>();
return true;
}
else if (triggerReason == SignatureHelpTriggerReason.InvokeSignatureHelpCommand)
}
else if (triggerReason == SignatureHelpTriggerReason.InvokeSignatureHelpCommand)
{
expression = token.Parent?.GetAncestorsOrThis<TSyntax>().SkipWhile(syntax => !isArgumentListToken(syntax, token)).FirstOrDefault();

@brettfo brettfo Mar 12, 2015

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The true diff is adding the conditional access on this line token.Parent?.GetAncestorsOrThis and on one line below.

return expression != null;
}
else if (triggerReason == SignatureHelpTriggerReason.RetriggerCommand)
{
if (!syntaxFacts.IsInNonUserCode(root.SyntaxTree, position, cancellationToken) ||
syntaxFacts.IsEntirelyWithinStringOrCharLiteral(root.SyntaxTree, position, cancellationToken))
{
expression = token.Parent.GetAncestorsOrThis<TSyntax>().SkipWhile(syntax => !isArgumentListToken(syntax, token)).FirstOrDefault();
expression = token.Parent?.AncestorsAndSelf()

@brettfo brettfo Mar 12, 2015

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The true diff is adding the conditional access on this line token.Parent?.AncestorsAndSelf and on one line above.

.TakeWhile(n => !syntaxFacts.IsAnonymousFunction(n))
.OfType<TSyntax>()
.SkipWhile(syntax => !isArgumentListToken(syntax, token))
.FirstOrDefault();
return expression != null;
}
else if (triggerReason == SignatureHelpTriggerReason.RetriggerCommand)
{
if (!syntaxFacts.IsInNonUserCode(root.SyntaxTree, position, cancellationToken) ||
syntaxFacts.IsEntirelyWithinStringOrCharLiteral(root.SyntaxTree, position, cancellationToken))
{
expression = token.Parent.AncestorsAndSelf()
.TakeWhile(n => !syntaxFacts.IsAnonymousFunction(n))
.OfType<TSyntax>()
.SkipWhile(syntax => !isArgumentListToken(syntax, token))
.FirstOrDefault();
return expression != null;
}
}

expression = null;
return false;
}
catch (NullReferenceException e) when (FatalError.Report(e))
{
throw ExceptionUtilities.Unreachable;
}

expression = null;
return false;
}
}
}