internal void ComputeReturnType()
{
if (!_lazyReturnType.IsNull)
{
return;
}
var diagnostics = DiagnosticBag.GetInstance();
TypeSyntax returnTypeSyntax = _syntax.ReturnType;
TypeSymbolWithAnnotations returnType = _binder.BindType(returnTypeSyntax, diagnostics);
if (this.IsAsync)
{
if (this.RefKind != RefKind.None)
{
ReportBadRefToken(returnTypeSyntax, diagnostics);
}
else if (returnType.TypeSymbol.IsBadAsyncReturn(this.DeclaringCompilation))
{
diagnostics.Add(ErrorCode.ERR_BadAsyncReturn, this.Locations[0]);
}
}
var location = _syntax.ReturnType.Location;
if (_refKind == RefKind.RefReadOnly)
{
DeclaringCompilation.EnsureIsReadOnlyAttributeExists(diagnostics, location, modifyCompilation: false);
}
if (returnType.NeedsNullableAttribute())
{
DeclaringCompilation.EnsureNullableAttributeExists(diagnostics, location, modifyCompilation: false);
// Note: we don't need to warn on annotations used without NonNullTypes context for local functions, as this is handled in binding already
}
// span-like types are returnable in general
if (returnType.IsRestrictedType(ignoreSpanLikeTypes: true))
{
// Method or delegate cannot return type '{0}'
diagnostics.Add(ErrorCode.ERR_MethodReturnCantBeRefAny, returnTypeSyntax.Location, returnType.TypeSymbol);
}
Debug.Assert(_refKind == RefKind.None ||
returnType.SpecialType != SpecialType.System_Void ||
returnTypeSyntax.HasErrors);
lock (_declarationDiagnostics)
{
if (!_lazyReturnType.IsNull)
{
diagnostics.Free();
return;
}
_declarationDiagnostics.AddRangeAndFree(diagnostics);
_lazyReturnType = returnType;
}
}
