private UnboundLambda BindAnonymousFunction(CSharpSyntaxNode syntax, DiagnosticBag diagnostics)
{
Debug.Assert(syntax != null);
Debug.Assert(syntax.IsAnonymousFunction());
var results = AnalyzeAnonymousFunction(syntax, diagnostics);
var refKinds = results.Item1;
var types = results.Item2;
var names = results.Item3;
var isAsync = results.Item4;
if (!types.IsDefault)
{
foreach (var type in types)
{
// UNDONE: Where do we report improper use of pointer types?
if (!type.IsNull && type.IsStatic)
{
Error(diagnostics, ErrorCode.ERR_ParameterIsStaticClass, syntax, type.TypeSymbol);
}
}
}
var lambda = new UnboundLambda(syntax, this, refKinds, types, names, isAsync);
if (!names.IsDefault)
{
var binder = new LocalScopeBinder(this);
bool allowShadowingNames = binder.Compilation.IsFeatureEnabled(MessageID.IDS_FeatureNameShadowingInNestedFunctions);
var pNames = PooledHashSet <string> .GetInstance();
for (int i = 0; i < lambda.ParameterCount; i++)
{
var name = lambda.ParameterName(i);
if (string.IsNullOrEmpty(name))
{
continue;
}
if (!pNames.Add(name))
{
// The parameter name '{0}' is a duplicate
diagnostics.Add(ErrorCode.ERR_DuplicateParamName, lambda.ParameterLocation(i), name);
}
else if (!allowShadowingNames)
{
binder.ValidateLambdaParameterNameConflictsInScope(lambda.ParameterLocation(i), name, diagnostics);
}
}
pNames.Free();
}
return(lambda);
}
// An anonymous function can be of the form:
//
// delegate { } (missing parameter list)
// delegate (int x) { } (typed parameter list)
// x => ... (type-inferred parameter list)
// (x) => ... (type-inferred parameter list)
// (x, y) => ... (type-inferred parameter list)
// ( ) => ... (typed parameter list)
// (ref int x) => ... (typed parameter list)
// (int x, out int y) => ... (typed parameter list)
//
// and so on. We want to canonicalize these various ways of writing the signatures.
//
// If we are in the first case then the name, modifier and type arrays are all null.
// If we have a parameter list then the names array is non-null, but possibly empty.
// If we have types then the types array is non-null, but possibly empty.
// If we have no modifiers then the modifiers array is null; if we have any modifiers
// then the modifiers array is non-null and not empty.
private Tuple <ImmutableArray <RefKind>, ImmutableArray <TypeSymbolWithAnnotations>, ImmutableArray <string>, bool> AnalyzeAnonymousFunction(
CSharpSyntaxNode syntax, DiagnosticBag diagnostics)
{
Debug.Assert(syntax != null);
Debug.Assert(syntax.IsAnonymousFunction());
var names = default(ImmutableArray <string>);
var refKinds = default(ImmutableArray <RefKind>);
var types = default(ImmutableArray <TypeSymbolWithAnnotations>);
bool isAsync = false;
var namesBuilder = ArrayBuilder <string> .GetInstance();
SeparatedSyntaxList <ParameterSyntax>?parameterSyntaxList = null;
bool hasSignature;
switch (syntax.Kind())
{
default:
case SyntaxKind.SimpleLambdaExpression:
// x => ...
hasSignature = true;
var simple = (SimpleLambdaExpressionSyntax)syntax;
namesBuilder.Add(simple.Parameter.Identifier.ValueText);
isAsync = (simple.AsyncKeyword.Kind() == SyntaxKind.AsyncKeyword);
break;
case SyntaxKind.ParenthesizedLambdaExpression:
// (T x, U y) => ...
// (x, y) => ...
hasSignature = true;
var paren = (ParenthesizedLambdaExpressionSyntax)syntax;
parameterSyntaxList = paren.ParameterList.Parameters;
CheckParenthesizedLambdaParameters(parameterSyntaxList.Value, diagnostics);
isAsync = (paren.AsyncKeyword.Kind() == SyntaxKind.AsyncKeyword);
break;
case SyntaxKind.AnonymousMethodExpression:
// delegate (int x) { }
// delegate { }
var anon = (AnonymousMethodExpressionSyntax)syntax;
hasSignature = anon.ParameterList != null;
if (hasSignature)
{
parameterSyntaxList = anon.ParameterList.Parameters;
}
isAsync = (anon.AsyncKeyword.Kind() == SyntaxKind.AsyncKeyword);
break;
}
if (parameterSyntaxList != null)
{
var hasExplicitlyTypedParameterList = true;
var allValue = true;
var typesBuilder = ArrayBuilder <TypeSymbolWithAnnotations> .GetInstance();
var refKindsBuilder = ArrayBuilder <RefKind> .GetInstance();
// In the batch compiler case we probably should have given a syntax error if the
// user did something like (int x, y)=>x+y -- but in the IDE scenario we might be in
// this case. If we are, then rather than try to make partial deductions from the
// typed formal parameters, simply bail out and treat it as an untyped lambda.
//
// However, we still want to give errors on every bad type in the list, even if one
// is missing.
foreach (var p in parameterSyntaxList.Value)
{
foreach (var attributeList in p.AttributeLists)
{
Error(diagnostics, ErrorCode.ERR_AttributesNotAllowed, attributeList);
}
if (p.Default != null)
{
Error(diagnostics, ErrorCode.ERR_DefaultValueNotAllowed, p.Default.EqualsToken);
}
if (p.IsArgList)
{
Error(diagnostics, ErrorCode.ERR_IllegalVarArgs, p);
continue;
}
var typeSyntax = p.Type;
TypeSymbolWithAnnotations type = default;
var refKind = RefKind.None;
if (typeSyntax == null)
{
hasExplicitlyTypedParameterList = false;
}
else
{
var extendedSyntax = typeSyntax as ExtendedTypeSyntax;
type = BindType(typeSyntax, diagnostics);
if (extendedSyntax != null)
{
foreach (var modifier in extendedSyntax.Modifiers)
{
switch (modifier.Kind())
{
case SyntaxKind.RefKeyword:
refKind = RefKind.Ref;
allValue = false;
break;
case SyntaxKind.OutKeyword:
refKind = RefKind.Out;
allValue = false;
break;
case SyntaxKind.InKeyword:
refKind = RefKind.In;
allValue = false;
break;
case SyntaxKind.ParamsKeyword:
// This was a parse error in the native compiler;
// it is a semantic analysis error in Roslyn. See comments to
// changeset 1674 for details.
Error(diagnostics, ErrorCode.ERR_IllegalParams, p);
break;
case SyntaxKind.ThisKeyword:
Error(diagnostics, ErrorCode.ERR_ThisInBadContext, modifier);
break;
}
}
}
}
namesBuilder.Add(p.Identifier.ValueText);
typesBuilder.Add(type);
refKindsBuilder.Add(refKind);
}
if (hasExplicitlyTypedParameterList)
{
types = typesBuilder.ToImmutable();
}
if (!allValue)
{
refKinds = refKindsBuilder.ToImmutable();
}
typesBuilder.Free();
refKindsBuilder.Free();
}
if (hasSignature)
{
names = namesBuilder.ToImmutable();
}
namesBuilder.Free();
return(Tuple.Create(refKinds, types, names, isAsync));
}