Fix #3621: Fix multiple uses of primary ctor parameter in initializer of record.

Author: siegfriedpammer

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

@@ -232,6 +232,17 @@ public UnexpectedCodeInCtor(int A)
 				this.A = A;
 			}
 		}
+
+		private record RecordWithMultipleInitializerAssignmentsInPrimaryCtor(string name, string? value, in object encode)
+		{
+			public string? Value { get; } = name;
+
+			public string Name { get; } = value;
+
+			private string? WebValue { get; } = (name != null) ? "111" : value;
+
+			private string? WebValue2;
+		}
 	}
 
 #if CS100

ICSharpCode.Decompiler/CSharp/RecordDecompiler.cs

@@ -303,13 +303,13 @@ bool IsPrimaryConstructor(Block body, IMethod method, IMethod unspecializedMetho
 						continue;
 					if (valueInst.MatchLdLoc(out var v))
 					{
-						if (v.Kind != VariableKind.Parameter || v.Index < parameterIndex)
+						if (!ValidateParameter(v, parameterIndex))
 							return false;
 						parameterIndex = v.Index!.Value;
 					}
 					else if (valueInst.MatchLdObj(out valueInst, out _) && valueInst.MatchLdLoc(out v))
 					{
-						if (v.Kind != VariableKind.Parameter || v.Index < parameterIndex)
+						if (!ValidateParameter(v, parameterIndex))
 							return false;
 						parameterIndex = v.Index!.Value;
 						if (method.Parameters[parameterIndex].ReferenceKind is ReferenceKind.None)
@@ -339,6 +339,19 @@ bool IsPrimaryConstructor(Block body, IMethod method, IMethod unspecializedMetho
 
 				var returnInst = body.Instructions.LastOrDefault();
 				return returnInst != null && returnInst.MatchReturn(out var retVal) && retVal.MatchNop();
+
+				bool ValidateParameter(ILVariable v, int expectedMinimumIndex)
+				{
+					if (v.Kind != VariableKind.Parameter)
+						return false;
+					Debug.Assert(v.Index.HasValue);
+					if (v.Index < 0 || v.Index >= unspecializedMethod.Parameters.Count)
+						return false;
+					var parameter = unspecializedMethod.Parameters[v.Index.Value];
+					if (primaryCtorParameterToAutoProperty.ContainsKey(parameter))
+						return true;
+					return v.Index >= expectedMinimumIndex;
+				}
 			}
 
 			IMethod? FindChainedCtor(Block body)