private void ComputeParameters()
        {
            if (_lazyParameters != null)
            {
                return;
            }

            SyntaxToken arglistToken;
            var         diagnostics = DiagnosticBag.GetInstance();

            var parameters = ParameterHelpers.MakeParameters(
                _binder,
                this,
                _syntax.ParameterList,
                arglistToken: out arglistToken,
                allowRefOrOut: true,
                allowThis: true,
                addRefReadOnlyModifier: false,
                diagnostics: diagnostics);

            var compilation = DeclaringCompilation;

            ParameterHelpers.EnsureIsReadOnlyAttributeExists(compilation, parameters, diagnostics, modifyCompilation: false);
            ParameterHelpers.EnsureNullableAttributeExists(compilation, this, parameters, diagnostics, modifyCompilation: false);
            // Note: we don't need to warn on annotations used in #nullable disable context for local functions, as this is handled in binding already

            var isVararg = arglistToken.Kind() == SyntaxKind.ArgListKeyword;

            if (isVararg)
            {
                diagnostics.Add(ErrorCode.ERR_IllegalVarArgs, arglistToken.GetLocation());
            }

            if (IsAsync)
            {
                SourceOrdinaryMethodSymbol.ReportAsyncParameterErrors(parameters, diagnostics, this.Locations[0]);
            }

            lock (_declarationDiagnostics)
            {
                if (_lazyParameters != null)
                {
                    diagnostics.Free();
                    return;
                }

                _declarationDiagnostics.AddRangeAndFree(diagnostics);
                _lazyIsVarArg   = isVararg;
                _lazyParameters = parameters;
            }
        }
        private void ComputeParameters()
        {
            if (_lazyParameters != null)
            {
                return;
            }

            SyntaxToken arglistToken;
            var         diagnostics = DiagnosticBag.GetInstance();

            var parameters = ParameterHelpers.MakeParameters(
                _binder,
                this,
                _syntax.ParameterList,
                arglistToken: out arglistToken,
                allowRefOrOut: true,
                allowThis: true,
                addRefReadOnlyModifier: false,
                diagnostics: diagnostics);

            ParameterHelpers.EnsureIsReadOnlyAttributeExists(parameters, diagnostics, modifyCompilationForRefReadOnly: false);

            var isVararg = arglistToken.Kind() == SyntaxKind.ArgListKeyword;

            if (isVararg)
            {
                diagnostics.Add(ErrorCode.ERR_IllegalVarArgs, arglistToken.GetLocation());
            }

            if (IsAsync)
            {
                SourceOrdinaryMethodSymbol.ReportAsyncParameterErrors(parameters, diagnostics, this.Locations[0]);
            }

            lock (_declarationDiagnostics)
            {
                if (_lazyParameters != null)
                {
                    diagnostics.Free();
                    return;
                }

                _declarationDiagnostics.AddRangeAndFree(diagnostics);
                _lazyIsVarArg   = isVararg;
                _lazyParameters = parameters;
            }
        }