Fix #3406: Wrong decompilation of record struct without primary constructor.

Author: siegfriedpammer

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -135,6 +135,7 @@
     <Compile Include="TestCases\ILPretty\Issue3442.cs" />
     <Compile Include="TestCases\ILPretty\MonoFixed.cs" />
     <Compile Include="TestCases\Pretty\Comparisons.cs" />
+    <Compile Include="TestCases\Pretty\Issue3406.cs" />
     <Compile Include="TestCases\Pretty\Issue3439.cs" />
     <Compile Include="TestCases\Pretty\Issue3442.cs" />
     <None Include="TestCases\VBPretty\VBAutomaticEvents.vb" />

ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs

@@ -610,6 +610,12 @@ public async Task Issue3439([ValueSource(nameof(defaultOptions))] CompilerOption
 			await RunForLibrary(cscOptions: cscOptions);
 		}
 
+		[Test]
+		public async Task Issue3406([ValueSource(nameof(roslyn4OrNewerOptions))] CompilerOptions cscOptions)
+		{
+			await RunForLibrary(cscOptions: cscOptions);
+		}
+
 		[Test]
 		public async Task Issue3442([ValueSource(nameof(defaultOptions))] CompilerOptions cscOptions)
 		{

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Issue3406.cs

@@ -0,0 +1,35 @@
+internal class Issue3406
+{
+	private record struct S1(int Value);
+
+	private record struct S2
+	{
+		public int Value;
+
+		public S2(int value)
+		{
+			Value = value;
+		}
+
+		public S2(int a, int b)
+		{
+			Value = a + b;
+		}
+	}
+
+	private record struct S3
+	{
+		public int Value;
+
+		public S3(int value)
+		{
+			Value = value;
+		}
+	}
+
+	// This also generates a hidden backing field
+	private record struct S4(int value)
+	{
+		public int Value = value;
+	}
+}

ICSharpCode.Decompiler/CSharp/RecordDecompiler.cs

@@ -222,10 +222,14 @@ bool IsPrimaryConstructor(IMethod method, IMethod unspecializedMethod)
 					{
 						backingMember = property;
 					}
-					else
+					else if (!recordTypeDef.IsRecord)
 					{
 						backingMember = field;
 					}
+					else
+					{
+						return false;
+					}
 
 					primaryCtorParameterToAutoPropertyOrBackingField.Add(unspecializedMethod.Parameters[i], backingMember);
 					autoPropertyOrBackingFieldToPrimaryCtorParameter.Add(backingMember, unspecializedMethod.Parameters[i]);

ICSharpCode.Decompiler/CSharp/Transforms/TransformFieldAndConstructorInitializers.cs

@@ -285,9 +285,9 @@ bool IsPropertyDeclaredByPrimaryCtor(IMember m, RecordDecompiler record)
 				case IProperty p:
 					return record.IsPropertyDeclaredByPrimaryConstructor(p);
 				case IField f:
-					return true;
+					return record.PrimaryConstructor != null;
 				case IEvent e:
-					return true;
+					return record.PrimaryConstructor != null;
 				default:
 					return false;
 			}