private static bool PreventsSuccessfulDelegateConversion(FirstAmongEqualsSet <Diagnostic> set)
{
foreach (var diagnostic in set)
{
if (ErrorFacts.PreventsSuccessfulDelegateConversion((ErrorCode)diagnostic.Code))
{
return(true);
}
}
return(false);
}
internal static bool PreventsSuccessfulDelegateConversion(DiagnosticBag diagnostics)
{
foreach (Diagnostic diag in diagnostics.AsEnumerable()) // Checking the code would have resolved them anyway.
{
if (ErrorFacts.PreventsSuccessfulDelegateConversion((ErrorCode)diag.Code))
{
return(true);
}
}
return(false);
}
internal static bool PreventsSuccessfulDelegateConversion(ImmutableArray <Diagnostic> diagnostics)
{
foreach (var diag in diagnostics)
{
if (ErrorFacts.PreventsSuccessfulDelegateConversion((ErrorCode)diag.Code))
{
return(true);
}
}
return(false);
}
/// <summary>
/// What we need to do is find a *repeatable* arbitrary way to choose between
/// two errors; we can for example simply take the one that is lower in alphabetical
/// order when converted to a string. As an optimization, we compare error codes
/// first and skip string comparison if they differ.
/// </summary>
private static int CanonicallyCompareDiagnostics(Diagnostic x, Diagnostic y)
{
ErrorCode xCode = (ErrorCode)x.Code;
ErrorCode yCode = (ErrorCode)y.Code;
int codeCompare = xCode.CompareTo(yCode);
// ToString fails for a diagnostic with an error code that does not prevernt successful delegate conversion.
// Also, the order doesn't matter, since all such diagnostics will be dropped.
if (!ErrorFacts.PreventsSuccessfulDelegateConversion(xCode) || !ErrorFacts.PreventsSuccessfulDelegateConversion(yCode))
{
return(codeCompare);
}
// Optimization: don't bother
return(codeCompare == 0 ? string.CompareOrdinal(x.ToString(), y.ToString()) : codeCompare);
}
private static LambdaConversionResult IsAnonymousFunctionCompatibleWithDelegate(UnboundLambda anonymousFunction, TypeSymbol type)
{
Debug.Assert((object)anonymousFunction != null);
Debug.Assert((object)type != null);
// SPEC: An anonymous-method-expression or lambda-expression is classified as an anonymous function.
// SPEC: The expression does not have a type but can be implicitly converted to a compatible delegate
// SPEC: type or expression tree type. Specifically, a delegate type D is compatible with an
// SPEC: anonymous function F provided:
var delegateType = (NamedTypeSymbol)type;
var invokeMethod = delegateType.DelegateInvokeMethod;
if ((object)invokeMethod == null || invokeMethod.HasUseSiteError)
{
return(LambdaConversionResult.BadTargetType);
}
var delegateParameters = invokeMethod.Parameters;
// SPEC: If F contains an anonymous-function-signature, then D and F have the same number of parameters.
// SPEC: If F does not contain an anonymous-function-signature, then D may have zero or more parameters
// SPEC: of any type, as long as no parameter of D has the out parameter modifier.
if (anonymousFunction.HasSignature)
{
if (anonymousFunction.ParameterCount != invokeMethod.ParameterCount)
{
return(LambdaConversionResult.BadParameterCount);
}
// SPEC: If F has an explicitly typed parameter list, each parameter in D has the same type
// SPEC: and modifiers as the corresponding parameter in F.
// SPEC: If F has an implicitly typed parameter list, D has no ref or out parameters.
if (anonymousFunction.HasExplicitlyTypedParameterList)
{
for (int p = 0; p < delegateParameters.Length; ++p)
{
if (delegateParameters[p].RefKind != anonymousFunction.RefKind(p) ||
!delegateParameters[p].Type.Equals(anonymousFunction.ParameterType(p), ignoreCustomModifiersAndArraySizesAndLowerBounds: true, ignoreDynamic: true))
{
return(LambdaConversionResult.MismatchedParameterType);
}
}
}
else
{
for (int p = 0; p < delegateParameters.Length; ++p)
{
if (delegateParameters[p].RefKind != RefKind.None)
{
return(LambdaConversionResult.RefInImplicitlyTypedLambda);
}
}
// In C# it is not possible to make a delegate type
// such that one of its parameter types is a static type. But static types are
// in metadata just sealed abstract types; there is nothing stopping someone in
// another language from creating a delegate with a static type for a parameter,
// though the only argument you could pass for that parameter is null.
//
// In the native compiler we forbid conversion of an anonymous function that has
// an implicitly-typed parameter list to a delegate type that has a static type
// for a formal parameter type. However, we do *not* forbid it for an explicitly-
// typed lambda (because we already require that the explicitly typed parameter not
// be static) and we do not forbid it for an anonymous method with the entire
// parameter list missing (because the body cannot possibly have a parameter that
// is of static type, even though this means that we will be generating a hidden
// method with a parameter of static type.)
//
// We also allow more exotic situations to work in the native compiler. For example,
// though it is not possible to convert x=>{} to Action<GC>, it is possible to convert
// it to Action<List<GC>> should there be a language that allows you to construct
// a variable of that type.
//
// We might consider beefing up this rule to disallow a conversion of *any* anonymous
// function to *any* delegate that has a static type *anywhere* in the parameter list.
for (int p = 0; p < delegateParameters.Length; ++p)
{
if (delegateParameters[p].Type.IsStatic)
{
return(LambdaConversionResult.StaticTypeInImplicitlyTypedLambda);
}
}
}
}
else
{
for (int p = 0; p < delegateParameters.Length; ++p)
{
if (delegateParameters[p].RefKind == RefKind.Out)
{
return(LambdaConversionResult.MissingSignatureWithOutParameter);
}
}
}
// Ensure the body can be converted to that delegate type
var bound = anonymousFunction.Bind(delegateType);
if (ErrorFacts.PreventsSuccessfulDelegateConversion(bound.Diagnostics))
{
return(LambdaConversionResult.BindingFailed);
}
return(LambdaConversionResult.Success);
}
public bool GenerateSummaryErrors(DiagnosticBag diagnostics)
{
// It is highly likely that "the same" error will be given for two different
// bindings of the same lambda but with different values for the parameters
// of the error. For example, if we have x=>x.Blah() where x could be int
// or string, then the two errors will be "int does not have member Blah" and
// "string does not have member Blah", but the locations and errors numbers
// will be the same.
//
// We should first see if there is a set of errors that are "the same" by
// this definition that occur in every lambda binding; if there are then
// those are the errors we should report.
//
// If there are no errors that are common to *every* binding then we
// can report the complete set of errors produced by every binding. However,
// we still wish to avoid duplicates, so we will use the same logic for
// building the union as the intersection; two errors with the same code
// and location are to be treated as the same error and only reported once,
// regardless of how that error is parameterized.
//
// The question then rears its head: when given two of "the same" error
// to report that are nevertheless different in their arguments, which one
// do we choose? To the user it hardly matters; either one points to the
// right location in source code. But it surely matters to our testing team;
// we do not want to be in a position where some small change to our internal
// representation of lambdas causes tests to break because errors are reported
// differently.
//
// What we need to do is find a *repeatable* arbitrary way to choose between
// two errors; we can for example simply take the one that is lower in alphabetical
// order when converted to a string.
var equalityComparer = new CommonDiagnosticComparer();
Func <Diagnostic, Diagnostic, int> canonicalComparer = CanonicallyCompareDiagnostics;
FirstAmongEqualsSet <Diagnostic> intersection = null;
var convBags = from boundLambda in bindingCache.Values select boundLambda.Diagnostics;
var retBags = from boundLambda in returnInferenceCache.Values select boundLambda.Diagnostics;
var allBags = convBags.Concat(retBags);
foreach (ImmutableArray <Diagnostic> bag in allBags)
{
if (intersection == null)
{
intersection = new FirstAmongEqualsSet <Diagnostic>(bag, equalityComparer, canonicalComparer);
}
else
{
intersection.IntersectWith(bag);
}
}
if (intersection != null)
{
foreach (var diagnostic in intersection)
{
if (ErrorFacts.PreventsSuccessfulDelegateConversion((ErrorCode)diagnostic.Code))
{
diagnostics.AddRange(intersection);
return(true);
}
}
}
FirstAmongEqualsSet <Diagnostic> union = null;
foreach (ImmutableArray <Diagnostic> bag in allBags)
{
if (union == null)
{
union = new FirstAmongEqualsSet <Diagnostic>(bag, equalityComparer, canonicalComparer);
}
else
{
union.UnionWith(bag);
}
}
if (union != null)
{
foreach (var diagnostic in union)
{
if (ErrorFacts.PreventsSuccessfulDelegateConversion((ErrorCode)diagnostic.Code))
{
diagnostics.AddRange(union);
return(true);
}
}
}
return(false);
}
private BoundLambda ReallyBind(NamedTypeSymbol delegateType)
{
var returnType = DelegateReturnType(delegateType);
LambdaSymbol lambdaSymbol;
Binder lambdaBodyBinder;
BoundBlock block;
var diagnostics = DiagnosticBag.GetInstance();
// when binding for real (not for return inference), there is still
// a good chance that we could reuse a body of a lambda previously bound for
// return type inference.
MethodSymbol cacheKey = GetCacheKey(delegateType);
BoundLambda returnInferenceLambda;
if (returnInferenceCache.TryGetValue(cacheKey, out returnInferenceLambda) && returnInferenceLambda.InferredFromSingleType)
{
var lambdaSym = returnInferenceLambda.Symbol;
var lambdaRetType = lambdaSym.ReturnType;
if (lambdaRetType == returnType)
{
lambdaSymbol = lambdaSym;
lambdaBodyBinder = returnInferenceLambda.Binder;
block = returnInferenceLambda.Body;
diagnostics.AddRange(returnInferenceLambda.Diagnostics);
goto haveLambdaBodyAndBinders;
}
}
var parameters = DelegateParameters(delegateType);
lambdaSymbol = new LambdaSymbol(binder.Compilation, binder.ContainingMemberOrLambda, this.unboundLambda, parameters, returnType);
lambdaBodyBinder = new ExecutableCodeBinder(this.unboundLambda.Syntax, lambdaSymbol, ParameterBinder(lambdaSymbol, binder));
block = BindLambdaBody(lambdaSymbol, ref lambdaBodyBinder, diagnostics);
ValidateUnsafeParameters(diagnostics, parameters);
haveLambdaBodyAndBinders:
bool reachableEndpoint = ControlFlowPass.Analyze(binder.Compilation, lambdaSymbol, block, diagnostics);
if (reachableEndpoint)
{
if (DelegateNeedsReturn(delegateType))
{
// Not all code paths return a value in {0} of type '{1}'
diagnostics.Add(ErrorCode.ERR_AnonymousReturnExpected, lambdaSymbol.Locations[0], this.MessageID.Localize(), delegateType);
}
else
{
block = FlowAnalysisPass.AppendImplicitReturn(block, lambdaSymbol, this.unboundLambda.Syntax);
}
}
if (IsAsync && !ErrorFacts.PreventsSuccessfulDelegateConversion(diagnostics))
{
if ((object)returnType != null && // Can be null if "delegateType" is not actually a delegate type.
returnType.SpecialType != SpecialType.System_Void &&
returnType != binder.Compilation.GetWellKnownType(WellKnownType.System_Threading_Tasks_Task) &&
returnType.OriginalDefinition != binder.Compilation.GetWellKnownType(WellKnownType.System_Threading_Tasks_Task_T))
{
// Cannot convert async {0} to delegate type '{1}'. An async {0} may return void, Task or Task<T>, none of which are convertible to '{1}'.
diagnostics.Add(ErrorCode.ERR_CantConvAsyncAnonFuncReturns, lambdaSymbol.Locations[0], lambdaSymbol.MessageID.Localize(), delegateType);
}
}
if (IsAsync)
{
Debug.Assert(lambdaSymbol.IsAsync);
SourceMemberMethodSymbol.ReportAsyncParameterErrors(lambdaSymbol, diagnostics, lambdaSymbol.Locations[0]);
}
var result = new BoundLambda(this.unboundLambda.Syntax, block, diagnostics.ToReadOnlyAndFree(), lambdaBodyBinder, delegateType)
{
WasCompilerGenerated = this.unboundLambda.WasCompilerGenerated
};
return(result);
}
private BoundLambda ReallyBind(NamedTypeSymbol delegateType)
{
var invokeMethod = DelegateInvokeMethod(delegateType);
RefKind refKind;
var returnType = DelegateReturnType(invokeMethod, out refKind);
LambdaSymbol lambdaSymbol;
Binder lambdaBodyBinder;
BoundBlock block;
var diagnostics = DiagnosticBag.GetInstance();
// when binding for real (not for return inference), there is still
// a good chance that we could reuse a body of a lambda previously bound for
// return type inference.
var cacheKey = ReturnInferenceCacheKey.Create(delegateType, IsAsync);
BoundLambda returnInferenceLambda;
if (_returnInferenceCache.TryGetValue(cacheKey, out returnInferenceLambda) && returnInferenceLambda.InferredFromSingleType)
{
lambdaSymbol = returnInferenceLambda.Symbol;
if ((object)LambdaSymbol.InferenceFailureReturnType != lambdaSymbol.ReturnType &&
lambdaSymbol.ReturnType == returnType && lambdaSymbol.RefKind == refKind)
{
lambdaBodyBinder = returnInferenceLambda.Binder;
block = returnInferenceLambda.Body;
diagnostics.AddRange(returnInferenceLambda.Diagnostics);
goto haveLambdaBodyAndBinders;
}
}
lambdaSymbol = new LambdaSymbol(
binder.Compilation,
binder.ContainingMemberOrLambda,
_unboundLambda,
cacheKey.ParameterTypes,
cacheKey.ParameterRefKinds,
refKind,
returnType);
lambdaBodyBinder = new ExecutableCodeBinder(_unboundLambda.Syntax, lambdaSymbol, ParameterBinder(lambdaSymbol, binder));
block = BindLambdaBody(lambdaSymbol, lambdaBodyBinder, diagnostics);
((ExecutableCodeBinder)lambdaBodyBinder).ValidateIteratorMethods(diagnostics);
ValidateUnsafeParameters(diagnostics, cacheKey.ParameterTypes);
haveLambdaBodyAndBinders:
bool reachableEndpoint = ControlFlowPass.Analyze(binder.Compilation, lambdaSymbol, block, diagnostics);
if (reachableEndpoint)
{
if (DelegateNeedsReturn(invokeMethod))
{
// Not all code paths return a value in {0} of type '{1}'
diagnostics.Add(ErrorCode.ERR_AnonymousReturnExpected, lambdaSymbol.DiagnosticLocation, this.MessageID.Localize(), delegateType);
}
else
{
block = FlowAnalysisPass.AppendImplicitReturn(block, lambdaSymbol);
}
}
if (IsAsync && !ErrorFacts.PreventsSuccessfulDelegateConversion(diagnostics))
{
if ((object)returnType != null && // Can be null if "delegateType" is not actually a delegate type.
returnType.SpecialType != SpecialType.System_Void &&
!returnType.IsNonGenericTaskType(binder.Compilation) &&
!returnType.IsGenericTaskType(binder.Compilation))
{
// Cannot convert async {0} to delegate type '{1}'. An async {0} may return void, Task or Task<T>, none of which are convertible to '{1}'.
diagnostics.Add(ErrorCode.ERR_CantConvAsyncAnonFuncReturns, lambdaSymbol.DiagnosticLocation, lambdaSymbol.MessageID.Localize(), delegateType);
}
}
if (IsAsync)
{
Debug.Assert(lambdaSymbol.IsAsync);
SourceMemberMethodSymbol.ReportAsyncParameterErrors(lambdaSymbol.Parameters, diagnostics, lambdaSymbol.DiagnosticLocation);
}
var result = new BoundLambda(_unboundLambda.Syntax, block, diagnostics.ToReadOnlyAndFree(), lambdaBodyBinder, delegateType, inferReturnType: false)
{
WasCompilerGenerated = _unboundLambda.WasCompilerGenerated
};
return(result);
}
private BoundLambda ReallyBind(NamedTypeSymbol delegateType)
{
var invokeMethod = DelegateInvokeMethod(delegateType);
RefKind refKind;
var returnType = DelegateReturnType(invokeMethod, out refKind);
LambdaSymbol lambdaSymbol;
Binder lambdaBodyBinder;
BoundBlock block;
var diagnostics = DiagnosticBag.GetInstance();
// when binding for real (not for return inference), there is still
// a good chance that we could reuse a body of a lambda previously bound for
// return type inference.
MethodSymbol cacheKey = GetCacheKey(delegateType);
BoundLambda returnInferenceLambda;
if (_returnInferenceCache.TryGetValue(cacheKey, out returnInferenceLambda) && returnInferenceLambda.InferredFromSingleType && returnInferenceLambda.Symbol.ReturnType == returnType)
{
lambdaSymbol = returnInferenceLambda.Symbol;
Debug.Assert(lambdaSymbol.RefKind == refKind);
lambdaBodyBinder = returnInferenceLambda.Binder;
block = returnInferenceLambda.Body;
diagnostics.AddRange(returnInferenceLambda.Diagnostics);
goto haveLambdaBodyAndBinders;
}
var parameters = DelegateParameters(invokeMethod);
lambdaSymbol = new LambdaSymbol(
binder.Compilation,
binder.ContainingMemberOrLambda,
_unboundLambda,
parameters,
refKind,
returnType);
lambdaBodyBinder = new ExecutableCodeBinder(_unboundLambda.Syntax, lambdaSymbol, ParameterBinder(lambdaSymbol, binder));
block = BindLambdaBody(lambdaSymbol, lambdaBodyBinder, diagnostics);
((ExecutableCodeBinder)lambdaBodyBinder).ValidateIteratorMethods(diagnostics);
ValidateUnsafeParameters(diagnostics, parameters);
haveLambdaBodyAndBinders:
bool reachableEndpoint = ControlFlowPass.Analyze(binder.Compilation, lambdaSymbol, block, diagnostics);
if (reachableEndpoint)
{
if (DelegateNeedsReturn(invokeMethod))
{
// Not all code paths return a value in {0} of type '{1}'
diagnostics.Add(ErrorCode.ERR_AnonymousReturnExpected, lambdaSymbol.Locations[0], this.MessageID.Localize(), delegateType);
}
else
{
block = FlowAnalysisPass.AppendImplicitReturn(block, lambdaSymbol);
}
}
if (IsAsync && !ErrorFacts.PreventsSuccessfulDelegateConversion(diagnostics))
{
if ((object)returnType != null && // Can be null if "delegateType" is not actually a delegate type.
returnType.SpecialType != SpecialType.System_Void &&
!returnType.IsNonGenericTaskType(binder.Compilation) &&
!returnType.IsGenericTaskType(binder.Compilation))
{
// Cannot convert async {0} to delegate type '{1}'. An async {0} may return void, Task or Task<T>, none of which are convertible to '{1}'.
diagnostics.Add(ErrorCode.ERR_CantConvAsyncAnonFuncReturns, lambdaSymbol.Locations[0], lambdaSymbol.MessageID.Localize(), delegateType);
}
}
if (IsAsync)
{
Debug.Assert(lambdaSymbol.IsAsync);
SourceMemberMethodSymbol.ReportAsyncParameterErrors(lambdaSymbol.Parameters, diagnostics, lambdaSymbol.Locations[0]);
}
// This is an attempt to get a repro for https://devdiv.visualstudio.com/DevDiv/_workitems?id=278481
if ((object)returnType != null && returnType.SpecialType != SpecialType.System_Void &&
!block.HasErrors && !diagnostics.HasAnyResolvedErrors() && block.Statements.Length > 0)
{
BoundStatement first = block.Statements[0];
if (first.Kind == BoundKind.ReturnStatement)
{
var returnStmt = (BoundReturnStatement)first;
if (returnStmt.ExpressionOpt != null && (object)returnStmt.ExpressionOpt.Type == null)
{
throw ExceptionUtilities.Unreachable;
}
}
}
var result = new BoundLambda(_unboundLambda.Syntax, block, diagnostics.ToReadOnlyAndFree(), lambdaBodyBinder, delegateType, inferReturnType: false)
{
WasCompilerGenerated = _unboundLambda.WasCompilerGenerated
};
return(result);
}