RecordDecompiler: nullable enable

ICSharpCode.Decompiler/CSharp/RecordDecompiler.cs

@@ -16,9 +16,12 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Reflection.Metadata;
 using System.Threading;
@@ -40,8 +43,8 @@ namespace ICSharpCode.Decompiler.CSharp
 		readonly bool isInheritedRecord;
 		readonly bool isStruct;
 		readonly bool isSealed;
-		readonly IMethod primaryCtor;
-		readonly IType baseClass;
+		readonly IMethod? primaryCtor;
+		readonly IType? baseClass;
 		readonly Dictionary<IField, IProperty> backingFieldToAutoProperty = new Dictionary<IField, IProperty>();
 		readonly Dictionary<IProperty, IField> autoPropertyToBackingField = new Dictionary<IProperty, IField>();
 		readonly Dictionary<IParameter, IProperty> primaryCtorParameterToAutoProperty = new Dictionary<IParameter, IProperty>();
@@ -76,7 +79,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				}
 			}
 
-			bool IsAutoProperty(IProperty p, out IField field)
+			bool IsAutoProperty(IProperty p, [NotNullWhen(true)] out IField? field)
 			{
 				field = null;
 				if (p.IsStatic)
@@ -109,7 +112,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				return field.Name == $"<{p.Name}>k__BackingField";
 			}
 
-			bool IsAutoGetter(IMethod method, out IField field)
+			bool IsAutoGetter(IMethod method, [NotNullWhen(true)] out IField? field)
 			{
 				field = null;
 				var body = DecompileBody(method);
@@ -130,7 +133,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				}
 			}
 
-			bool IsAutoSetter(IMethod method, out IField field)
+			bool IsAutoSetter(IMethod method, [NotNullWhen(true)] out IField? field)
 			{
 				field = null;
 				Debug.Assert(!method.IsStatic);
@@ -138,7 +141,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				if (body == null)
 					return false;
 				// this.field = value;
-				ILInstruction valueInst;
+				ILInstruction? valueInst;
 				if (method.IsStatic)
 				{
 					if (!body.Instructions[0].MatchStsFld(out field, out valueInst))
@@ -159,7 +162,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
-		IMethod DetectPrimaryConstructor()
+		IMethod? DetectPrimaryConstructor()
 		{
 			Debug.Assert(recordTypeDef.IsRecord);
 			if (!settings.UsePrimaryConstructorSyntax)
@@ -168,14 +171,14 @@ namespace ICSharpCode.Decompiler.CSharp
 			var subst = recordTypeDef.AsParameterizedType().GetSubstitution();
 
 			Dictionary<string, IMember> nameToMemberMap = new Dictionary<string, IMember>(StringComparer.Ordinal);
-			Dictionary<IMethod, IMethod> ctorChainMap = new Dictionary<IMethod, IMethod>();
+			Dictionary<IMethod, IMethod?> ctorChainMap = new Dictionary<IMethod, IMethod?>();
 
 			foreach (IMember m in recordTypeDef.GetMembers(m => m.SymbolKind is SymbolKind.Property or SymbolKind.Field, GetMemberOptions.ReturnMemberDefinitions))
 			{
 				nameToMemberMap[m.Name] = m;
 			}
 
-			IMethod guessedPrimaryCtor = null;
+			IMethod? guessedPrimaryCtor = null;
 
 			foreach (var method in recordTypeDef.Methods)
 			{
@@ -191,10 +194,10 @@ namespace ICSharpCode.Decompiler.CSharp
 				{
 					continue;
 				}
-				IMethod chainedCtor = (IMethod)FindChainedCtor(body)?.MemberDefinition;
+				IMethod? chainedCtor = (IMethod?)FindChainedCtor(body)?.MemberDefinition;
 				ctorChainMap[method] = chainedCtor;
 
-				if (chainedCtor != null && chainedCtor.DeclaringTypeDefinition.Equals(recordTypeDef))
+				if (chainedCtor != null && chainedCtor.DeclaringTypeDefinition!.Equals(recordTypeDef))
 				{
 					continue;
 				}
@@ -242,7 +245,7 @@ namespace ICSharpCode.Decompiler.CSharp
 
 			foreach (var (parameter, property) in primaryCtorParameterToAutoProperty.ToArray())
 			{
-				if (!parameter.Owner.Equals(guessedPrimaryCtor))
+				if (!parameter.Owner!.Equals(guessedPrimaryCtor))
 				{
 					primaryCtorParameterToAutoProperty.Remove(parameter);
 				}
@@ -302,13 +305,13 @@ namespace ICSharpCode.Decompiler.CSharp
 					{
 						if (v.Kind != VariableKind.Parameter || v.Index < parameterIndex)
 							return false;
-						parameterIndex = v.Index.Value;
+						parameterIndex = v.Index!.Value;
 					}
 					else if (valueInst.MatchLdObj(out valueInst, out _) && valueInst.MatchLdLoc(out v))
 					{
 						if (v.Kind != VariableKind.Parameter || v.Index < parameterIndex)
 							return false;
-						parameterIndex = v.Index.Value;
+						parameterIndex = v.Index!.Value;
 						if (method.Parameters[parameterIndex].ReferenceKind is ReferenceKind.None)
 						{
 							return false;
@@ -338,7 +341,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				return returnInst != null && returnInst.MatchReturn(out var retVal) && retVal.MatchNop();
 			}
 
-			IMethod FindChainedCtor(Block body)
+			IMethod? FindChainedCtor(Block body)
 			{
 				// look for a call instruction or assignment to a chained constructor
 				foreach (var inst in body.Instructions)
@@ -379,7 +382,7 @@ namespace ICSharpCode.Decompiler.CSharp
 		/// <summary>
 		/// Gets the detected primary constructor. Returns null, if there was no primary constructor detected.
 		/// </summary>
-		public IMethod PrimaryConstructor => primaryCtor;
+		public IMethod? PrimaryConstructor => primaryCtor;
 
 		public bool IsInheritedRecord => isInheritedRecord;
 
@@ -472,9 +475,9 @@ namespace ICSharpCode.Decompiler.CSharp
 				&& autoPropertyToPrimaryCtorParameter.ContainsKey((IProperty)property.Specialize(subst));
 		}
 
-		internal Dictionary<IParameter, (IProperty, IField)> GetParameterToBackingStoreMap()
+		internal Dictionary<IParameter, (IProperty?, IField)> GetParameterToBackingStoreMap()
 		{
-			var result = new Dictionary<IParameter, (IProperty, IField)>();
+			var result = new Dictionary<IParameter, (IProperty?, IField)>();
 			foreach (var (parameter, property) in primaryCtorParameterToAutoProperty)
 			{
 				result.Add(parameter, (property, autoPropertyToBackingField[property]));
@@ -549,7 +552,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			{
 				if (!(member is IField field))
 				{
-					if (!autoPropertyToBackingField.TryGetValue((IProperty)member, out field))
+					if (!autoPropertyToBackingField.TryGetValue((IProperty)member, out field!))
 						continue;
 				}
 				if (pos >= body.Instructions.Count)
@@ -668,7 +671,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				trueInst = Block.Unwrap(trueInst);
 				if (!MatchStringBuilderAppend(trueInst, builder, out var val))
 					return false;
-				if (!(val.MatchLdStr(out string text) && text == ", "))
+				if (!(val.MatchLdStr(out string? text) && text == ", "))
 					return false;
 				pos++;
 
@@ -700,7 +703,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				callvirt Append(ldloc builder, ldstr " = ")
 				callvirt Append(ldloc builder, constrained[System.Int32].callvirt ToString(ldflda B(ldloc this)))
 				leave IL_0000 (ldc.i4 1) */
-				if (!MatchStringBuilderAppendConstant(out string text))
+				if (!MatchStringBuilderAppendConstant(out string? text))
 					return false;
 				string expectedText = (needsComma ? ", " : "") + member.Name + " = ";
 				if (text != expectedText)
@@ -775,10 +778,10 @@ namespace ICSharpCode.Decompiler.CSharp
 				return true;
 			}
 
-			bool MatchStringBuilderAppendConstant(out string text)
+			bool MatchStringBuilderAppendConstant([NotNullWhen(true)] out string? text)
 			{
 				text = null;
-				while (MatchStringBuilderAppend(body.Instructions[pos], builder, out var val) && val.MatchLdStr(out string valText))
+				while (MatchStringBuilderAppend(body.Instructions[pos], builder, out var val) && val.MatchLdStr(out string? valText))
 				{
 					text += valText;
 					pos++;
@@ -787,7 +790,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
-		private bool MatchStringBuilderAppend(ILInstruction inst, ILVariable sb, out ILInstruction val)
+		private bool MatchStringBuilderAppend(ILInstruction inst, ILVariable sb, [NotNullWhen(true)] out ILInstruction? val)
 		{
 			val = null;
 			if (!(inst is CallVirt { Method: { Name: "Append", DeclaringType: { Namespace: "System.Text", Name: "StringBuilder" } } } call))
@@ -863,7 +866,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				{
 					return val != null && val.Length == 1 && call.Arguments[1].MatchLdcI4(val[0]);
 				}
-				return call.Arguments[1].MatchLdStr(out string val1) && val1 == val;
+				return call.Arguments[1].MatchLdStr(out string? val1) && val1 == val;
 			}
 		}
 
@@ -1015,7 +1018,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
-		private bool MatchGetEqualityContract(ILInstruction inst, out ILInstruction target)
+		private bool MatchGetEqualityContract(ILInstruction inst, [NotNullWhen(true)] out ILInstruction? target)
 		{
 			target = null;
 			if (!(inst is CallInstruction { Method: { Name: "get_EqualityContract" } } call))
@@ -1149,7 +1152,7 @@ namespace ICSharpCode.Decompiler.CSharp
 
 		bool IsGeneratedDeconstruct(IMethod method)
 		{
-			Debug.Assert(method.Name == "Deconstruct" && method.Parameters.Count == primaryCtor.Parameters.Count);
+			Debug.Assert(method.Name == "Deconstruct" && method.Parameters.Count == primaryCtor?.Parameters.Count);
 
 			if (!method.ReturnType.IsKnownType(KnownTypeCode.Void))
 				return false;
@@ -1205,7 +1208,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			return returnInst != null && returnInst.MatchReturn(out var retVal) && retVal.MatchNop();
 		}
 
-		bool MatchMemberAccess(ILInstruction inst, out ILInstruction target, out IMember member)
+		bool MatchMemberAccess(ILInstruction inst, [NotNullWhen(true)] out ILInstruction? target, [NotNullWhen(true)] out IMember? member)
 		{
 			target = null;
 			member = null;
@@ -1222,9 +1225,9 @@ namespace ICSharpCode.Decompiler.CSharp
 				member = property;
 				return true;
 			}
-			else if (inst.MatchLdFld(out target, out IField field))
+			else if (inst.MatchLdFld(out target, out IField? field))
 			{
-				if (backingFieldToAutoProperty.TryGetValue(field, out property))
+				if (backingFieldToAutoProperty.TryGetValue(field, out property!))
 					member = property;
 				else
 					member = field;
@@ -1236,7 +1239,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
-		Block DecompileBody(IMethod method)
+		Block? DecompileBody(IMethod method)
 		{
 			if (method == null || method.MetadataToken.IsNil)
 				return null;