diff --git a/ICSharpCode.Decompiler.Tests/TestCases/Correctness/LambdaNaturalType.cs b/ICSharpCode.Decompiler.Tests/TestCases/Correctness/LambdaNaturalType.cs
index 722604e21..33c5ffac0 100644
--- a/ICSharpCode.Decompiler.Tests/TestCases/Correctness/LambdaNaturalType.cs
+++ b/ICSharpCode.Decompiler.Tests/TestCases/Correctness/LambdaNaturalType.cs
@@ -74,12 +74,8 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 			var optionalParameter = (int x = 5) => x * 2;
 			Console.WriteLine("optional parameter: " + optionalParameter() + " " + optionalParameter(7));
 
-#if CS140
-			// Roslyn 4.14 emits no ParamArrayAttribute on a lambda's method, so 'params' cannot
-			// be recovered there and the decompiled call would no longer bind in expanded form.
 			var paramsParameter = (params int[] xs) => xs.Length;
 			Console.WriteLine("params parameter: " + paramsParameter(1, 2, 3));
-#endif
 		}
 	}
 }
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/Pretty/LambdaOptionalAndParamsParameters.cs b/ICSharpCode.Decompiler.Tests/TestCases/Pretty/LambdaOptionalAndParamsParameters.cs
index d4dec77ab..b9fa0b055 100644
--- a/ICSharpCode.Decompiler.Tests/TestCases/Pretty/LambdaOptionalAndParamsParameters.cs
+++ b/ICSharpCode.Decompiler.Tests/TestCases/Pretty/LambdaOptionalAndParamsParameters.cs
@@ -12,35 +12,15 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 
 		public ParamsAction ParamsStatementBody()
 		{
-#if CS140
 			return (params int[] xs) => {
 				total += xs.Length;
 				Console.WriteLine(xs.Length);
 			};
-#elif EXPECTED_OUTPUT
-			// Roslyn 4.14 does not emit ParamArrayAttribute on the lambda's method, so the
-			// 'params' modifier cannot be recovered from metadata.
-			return delegate (int[] xs) {
-				total += xs.Length;
-				Console.WriteLine(xs.Length);
-			};
-#else
-			return (params int[] xs) => {
-				total += xs.Length;
-				Console.WriteLine(xs.Length);
-			};
-#endif
 		}
 
 		public ParamsAction ParamsExpressionBody()
 		{
-#if EXPECTED_OUTPUT && !CS140
-			return delegate (int[] xs) {
-				Console.WriteLine(xs.Length);
-			};
-#else
 			return (params int[] xs) => Console.WriteLine(xs.Length);
-#endif
 		}
 
 		public OptionalFunc OptionalStatementBody()
diff --git a/ICSharpCode.Decompiler.Tests/UglyTestRunner.cs b/ICSharpCode.Decompiler.Tests/UglyTestRunner.cs
index 402085354..207b92edb 100644
--- a/ICSharpCode.Decompiler.Tests/UglyTestRunner.cs
+++ b/ICSharpCode.Decompiler.Tests/UglyTestRunner.cs
@@ -104,16 +104,16 @@ namespace ICSharpCode.Decompiler.Tests
 			CompilerOptions.Optimize | CompilerOptions.UseRoslynLatest,
 		});
 
-		// Roslyn 4.14 does not emit ParamArrayAttribute on synthesized lambda methods, so tests
-		// pinning its round-trip need the current compiler only.
-		static readonly CompilerOptions[] roslynLatestOnlyOptions = Tester.SupportedOnCurrentPlatform(new[]
+		static readonly CompilerOptions[] roslyn4OrNewerOptions = Tester.SupportedOnCurrentPlatform(new[]
 		{
+			CompilerOptions.UseRoslyn4_14_0,
+			CompilerOptions.Optimize | CompilerOptions.UseRoslyn4_14_0,
 			CompilerOptions.UseRoslynLatest,
 			CompilerOptions.Optimize | CompilerOptions.UseRoslynLatest,
 		});
 
 		[Test]
-		public async Task NoLambdaOptionalAndParamsParameters([ValueSource(nameof(roslynLatestOnlyOptions))] CompilerOptions cscOptions)
+		public async Task NoLambdaOptionalAndParamsParameters([ValueSource(nameof(roslyn4OrNewerOptions))] CompilerOptions cscOptions)
 		{
 			await RunForLibrary(cscOptions: cscOptions, decompilerSettings: new DecompilerSettings(CSharp.LanguageVersion.CSharp11_0) {
 				FileScopedNamespaces = false
diff --git a/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs b/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs
index 1291a087c..864cd7ccd 100644
--- a/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs
+++ b/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs
@@ -2543,6 +2543,26 @@ namespace ICSharpCode.Decompiler.CSharp
 			AnonymousMethodExpression ame = new AnonymousMethodExpression();
 			ame.IsAsync = function.IsAsync;
 			ame.Parameters.AddRange(MakeParameters(function.Parameters, function));
+			// 'params' and parameter default values are part of the delegate's signature, and it
+			// is the delegate's Invoke method that call sites bind against. An anonymous function's
+			// own method does not reliably carry them - Roslyn 4.14 emits no ParamArrayAttribute
+			// there - so take them from Invoke, keeping declaration and call sites consistent.
+			var invokeParameters = delegateType.GetDelegateInvokeMethod()?.Parameters;
+			if (invokeParameters?.Count == ame.Parameters.Count)
+			{
+				int parameterIndex = 0;
+				foreach (var pd in ame.Parameters)
+				{
+					var invokeParameter = invokeParameters[parameterIndex++];
+					pd.IsParams |= invokeParameter.IsParams;
+					if (pd.DefaultExpression is null
+						&& astBuilder.ConvertParameter(invokeParameter).DefaultExpression is { } defaultValue)
+					{
+						defaultValue.Detach();
+						pd.DefaultExpression = defaultValue;
+					}
+				}
+			}
 			var builder = new StatementBuilder(
 				typeSystem,
 				this.decompilationContext,