public BoundLambda BindForReturnTypeInference(NamedTypeSymbol delegateType)
{
var cacheKey = ReturnInferenceCacheKey.Create(delegateType, IsAsync);
BoundLambda result;
if (!_returnInferenceCache.TryGetValue(cacheKey, out result))
{
result = ReallyInferReturnType(delegateType, cacheKey.ParameterTypes, cacheKey.ParameterRefKinds);
result = ImmutableInterlocked.GetOrAdd(ref _returnInferenceCache, cacheKey, result);
}
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,
diagnostics);
lambdaBodyBinder = new ExecutableCodeBinder(_unboundLambda.Syntax, lambdaSymbol, ParameterBinder(lambdaSymbol, binder));
if (lambdaSymbol.RefKind == CodeAnalysis.RefKind.RefReadOnly)
{
binder.Compilation.EnsureIsReadOnlyAttributeExists(diagnostics, lambdaSymbol.DiagnosticLocation, modifyCompilationForRefReadOnly: false);
}
ParameterHelpers.EnsureIsReadOnlyAttributeExists(lambdaSymbol.Parameters, diagnostics, modifyCompilationForRefReadOnly: false);
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);
SourceOrdinaryMethodSymbol.ReportAsyncParameterErrors(lambdaSymbol.Parameters, diagnostics, lambdaSymbol.DiagnosticLocation);
}
var result = new BoundLambda(_unboundLambda.Syntax, block, diagnostics.ToReadOnlyAndFree(), lambdaBodyBinder, delegateType, inferReturnType: false)
{
WasCompilerGenerated = _unboundLambda.WasCompilerGenerated
};
return(result);
}
