Keep instance-dependent assignments in constructors

A moved field initializer cannot read another instance member. Reject primary-constructor conversion for that case and preserve the original constructor.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 0dd407b6-9410-48df-add5-761ca4a8dec0

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

@@ -134,6 +134,19 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 
 			public int B = b;
 		}
+
+		private struct StructInitializerDependsOnField
+		{
+			public int A;
+
+			public int B;
+
+			public StructInitializerDependsOnField(int value)
+			{
+				A = value;
+				B = A + 1;
+			}
+		}
 #endif
 
 		public class ClassWithConstant

ICSharpCode.Decompiler/CSharp/Transforms/TransformFieldAndConstructorInitializers.cs

@@ -356,6 +356,7 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					var initializer = InitializerSequence.Analyze(this, ctor, ctorMethod);
 
 					if (initializer is { CoversFullBody: true, HasDuplicateAssignments: false, Statements.Count: > 0 }
+						&& !initializer.Statements.Any(statement => ReferencesInstanceMember(statement.Initializer))
 						&& ctorMethod.Accessibility == expectedCtorAccessibility)
 					{
 						bool transformToPrimaryConstructor = MetadataTokens.GetRowNumber(ctorMethod.MetadataToken) == firstMethodRowNumber;
@@ -403,6 +404,24 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					}
 				}
 
+				bool ReferencesInstanceMember(Expression expression)
+				{
+					foreach (var node in expression.DescendantsAndSelf.OfType<Expression>())
+					{
+						switch (node.GetResolveResult())
+						{
+							case ThisResolveResult:
+								return true;
+							case MemberResolveResult {
+								TargetResult: ThisResolveResult,
+								Member: { IsStatic: false } member
+							} when member is not IField field || !IsGeneratedPrimaryConstructorBackingField(field):
+								return true;
+						}
+					}
+					return false;
+				}
+
 				if (StaticConstructor != null)
 				{
 					StaticInitializers = InitializerSequence.Analyze(this, StaticConstructorDecl!, StaticConstructor);