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Merged
AlekseyTs merged 3 commits into from
Mar 16, 2020
Merged

Support using local declarations in a Simple Program. #42385

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317013d
Support `using` local declarations in a Simple Program.
AlekseyTs Mar 13, 2020
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AlekseyTs Mar 13, 2020
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AlekseyTs Mar 13, 2020
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79 changes: 60 additions & 19 deletions src/Compilers/CSharp/Portable/Parser/LanguageParser.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -449,11 +449,10 @@ private void ParseNamespaceBody(ref SyntaxToken openBrace, ref NamespaceBodyBuil
}

case SyntaxKind.UsingKeyword:
if (isGlobal && this.PeekToken(1).Kind == SyntaxKind.OpenParenToken)
if (isGlobal && (this.PeekToken(1).Kind == SyntaxKind.OpenParenToken || (!IsScript && IsPossibleTopLevelUsingLocalDeclarationStatement())))
{
// incomplete members must be processed before we add any nodes to the body:
AddIncompleteMembers(ref pendingIncompleteMembers, ref body);
body.Members.Add(adjustStateAndReportStatementOutOfOrder(ref seen, ParseTopLevelUsingStatement()));
// Top-level using statement or using local declaration
goto default;
}
else
{
Expand Down Expand Up @@ -591,20 +590,6 @@ MemberDeclarationSyntax adjustStateAndReportStatementOutOfOrder(ref NamespacePar
}
}

[MethodImpl(MethodImplOptions.NoInlining)]
private GlobalStatementSyntax ParseTopLevelUsingStatement()
{
bool wasInAsync = IsInAsync;
if (!IsScript)
{
IsInAsync = true; // We are implicitly in an async context
}

var topLevelUsingStatement = CheckSimpleProgramsFeatureAvailability(_syntaxFactory.GlobalStatement(ParseUsingStatement(attributes: default)));
IsInAsync = wasInAsync;
return topLevelUsingStatement;
}

private GlobalStatementSyntax CheckSimpleProgramsFeatureAvailability(GlobalStatementSyntax globalStatementSyntax)
{
if (IsScript || _checkedSimpleProgramsFeatureAvailability)
Expand Down Expand Up @@ -2374,7 +2359,6 @@ static bool isAcceptableNonDeclarationStatement(StatementSyntax statement, bool
switch (statement?.Kind)
{
case null:
case SyntaxKind.LocalDeclarationStatement:
case SyntaxKind.LocalFunctionStatement:
case SyntaxKind.ExpressionStatement when
!isScript &&
Expand All @@ -2386,6 +2370,9 @@ static bool isAcceptableNonDeclarationStatement(StatementSyntax statement, bool

return false;

case SyntaxKind.LocalDeclarationStatement:
return !isScript && ((LocalDeclarationStatementSyntax)statement).UsingKeyword is object;

default:
return true;
}
Expand Down Expand Up @@ -6957,6 +6944,11 @@ private bool IsPossibleLocalDeclarationStatement(bool isGlobalScriptLevel)
return true;
}

return IsPossibleFirstTypedIdentifierInLocaDeclarationStatement(isGlobalScriptLevel);
}

private bool IsPossibleFirstTypedIdentifierInLocaDeclarationStatement(bool isGlobalScriptLevel)
{
bool? typedIdentifier = IsPossibleTypedIdentifierStart(this.CurrentToken, this.PeekToken(1), allowThisKeyword: false);
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@cston cston Mar 13, 2020 •
edited by AlekseyTs
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Extra blank line. #Resolved

if (typedIdentifier != null)
{
Expand All @@ -6978,6 +6970,8 @@ private bool IsPossibleLocalDeclarationStatement(bool isGlobalScriptLevel)
//
// Note that we explicitly do this check when we see that the code spreads over multiple
// lines. We don't want this if the user has actually written "X.Y z"
var tk = this.CurrentToken.ContextualKind;

if (tk == SyntaxKind.IdentifierToken)
{
var token1 = PeekToken(1);
Expand Down Expand Up @@ -7053,6 +7047,53 @@ private bool IsPossibleLocalDeclarationStatement(bool isGlobalScriptLevel)
}
}

private bool IsPossibleTopLevelUsingLocalDeclarationStatement()
{
if (this.CurrentToken.Kind != SyntaxKind.UsingKeyword)
{
return false;
}

var tk = PeekToken(1).Kind;

if (tk == SyntaxKind.RefKeyword)
{
return true;
}

if (IsDeclarationModifier(tk)) // treat `const int x = 2;` as a local variable declaration
{
if (tk != SyntaxKind.StaticKeyword) // For `static` we still need to make sure we have a typed identifier after it, because `using static type;` is a valid using directive.
{
return true;
}
}
else if (SyntaxFacts.IsPredefinedType(tk))
{
return true;
}

var resetPoint = this.GetResetPoint();
try
{
// Skip 'using' keyword
EatToken();

if (tk == SyntaxKind.StaticKeyword)
{
// Skip 'static' keyword
EatToken();
}

return IsPossibleFirstTypedIdentifierInLocaDeclarationStatement(isGlobalScriptLevel: false);
}
finally
{
this.Reset(ref resetPoint);
this.Release(ref resetPoint);
}
}

// Looks ahead for a declaration of a field, property or method declaration following a nullable type T?.
private bool IsPossibleDeclarationStatementFollowingNullableType()
{
Expand Down
21 changes: 21 additions & 0 deletions src/Compilers/CSharp/Test/Semantic/Semantics/SimpleProgramsTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -726,6 +726,27 @@ ref int local(bool flag, ref int a, ref int b)
CompileAndVerify(comp, expectedOutput: "100 200 300", verify: Verification.Skipped);
}

[Fact]
public void LocalDeclarationStatement_09()
{
var text = @"
using var a = new MyDisposable();
System.Console.Write(1);

class MyDisposable : System.IDisposable
{
public void Dispose()
{
System.Console.Write(2);
}
}
";

var comp = CreateCompilation(text, options: TestOptions.DebugExe, parseOptions: DefaultParseOptions);

CompileAndVerify(comp, expectedOutput: "12", verify: Verification.Skipped);
}

[Fact]
public void LocalUsedBeforeDeclaration_01()
{
Expand Down
9 changes: 5 additions & 4 deletions src/Compilers/CSharp/Test/Symbol/Compilation/GetSemanticInfoBrokenCodeTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -195,11 +195,12 @@ public void Repro611177()
var tree = comp.SyntaxTrees.Single();
var model = comp.GetSemanticModel(tree);

var usingSyntax = tree.GetCompilationUnitRoot().DescendantNodes().OfType<UsingDirectiveSyntax>().Single();
model.GetSymbolInfo(usingSyntax);
Assert.Empty(tree.GetCompilationUnitRoot().DescendantNodes().OfType<UsingDirectiveSyntax>());

var identifierSyntax = tree.GetCompilationUnitRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Single();
model.GetSymbolInfo(identifierSyntax);
foreach (var identifierSyntax in tree.GetCompilationUnitRoot().DescendantNodes().OfType<IdentifierNameSyntax>())
{
model.GetSymbolInfo(identifierSyntax);
}
}

[WorkItem(611177, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/611177")]
Expand Down
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