enable nullable annotations in SMAPI where no logic changes are needed (#837)

5 files changed, 31 insertions, 38 deletions

diff --git a/src/SMAPI/Framework/ModLoading/Rewriters/HarmonyRewriter.cs b/src/SMAPI/Framework/ModLoading/Rewriters/HarmonyRewriter.cs
index 92397c58..aea490c8 100644
--- a/src/SMAPI/Framework/ModLoading/Rewriters/HarmonyRewriter.cs
+++ b/src/SMAPI/Framework/ModLoading/Rewriters/HarmonyRewriter.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using HarmonyLib;
 using Mono.Cecil;
@@ -59,7 +57,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
             if (this.ShouldRewrite)
             {
                 // rewrite Harmony 1.x methods to Harmony 2.0
-                MethodReference methodRef = RewriteHelper.AsMethodReference(instruction);
+                MethodReference? methodRef = RewriteHelper.AsMethodReference(instruction);
                 if (this.TryRewriteMethodsToFacade(module, methodRef))
                 {
                     this.OnChanged();
@@ -67,7 +65,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
                 }
 
                 // rewrite renamed fields
-                FieldReference fieldRef = RewriteHelper.AsFieldReference(instruction);
+                FieldReference? fieldRef = RewriteHelper.AsFieldReference(instruction);
                 if (fieldRef != null)
                 {
                     if (fieldRef.DeclaringType.FullName == "HarmonyLib.HarmonyMethod" && fieldRef.Name == "prioritiy")
@@ -95,13 +93,13 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         /// <summary>Rewrite methods to use Harmony facades if needed.</summary>
         /// <param name="module">The assembly module containing the method reference.</param>
         /// <param name="methodRef">The method reference to map.</param>
-        private bool TryRewriteMethodsToFacade(ModuleDefinition module, MethodReference methodRef)
+        private bool TryRewriteMethodsToFacade(ModuleDefinition module, MethodReference? methodRef)
         {
             if (!this.ReplacedTypes)
                 return false; // not Harmony (or already using Harmony 2.0)
 
             // get facade type
-            Type toType = methodRef?.DeclaringType.FullName switch
+            Type? toType = methodRef?.DeclaringType.FullName switch
             {
                 "HarmonyLib.Harmony" => typeof(HarmonyInstanceFacade),
                 "HarmonyLib.AccessTools" => typeof(AccessToolsFacade),
@@ -112,9 +110,9 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
                 return false;
 
             // map if there's a matching method
-            if (RewriteHelper.HasMatchingSignature(toType, methodRef))
+            if (RewriteHelper.HasMatchingSignature(toType, methodRef!))
             {
-                methodRef.DeclaringType = module.ImportReference(toType);
+                methodRef!.DeclaringType = module.ImportReference(toType);
                 return true;
             }
 
@@ -139,7 +137,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         {
             string fullName = type.FullName.Replace("Harmony.", "HarmonyLib.");
             string targetName = typeof(Harmony).AssemblyQualifiedName!.Replace(typeof(Harmony).FullName!, fullName);
-            return Type.GetType(targetName, throwOnError: true);
+            return Type.GetType(targetName, throwOnError: true)!;
         }
     }
 }
diff --git a/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicFieldRewriter.cs b/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicFieldRewriter.cs
index fc06e779..9c6a3980 100644
--- a/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicFieldRewriter.cs
+++ b/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicFieldRewriter.cs
@@ -1,6 +1,5 @@
-#nullable disable
-
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
@@ -33,17 +32,17 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         public override bool Handle(ModuleDefinition module, ILProcessor cil, Instruction instruction)
         {
             // get field ref
-            FieldReference fieldRef = RewriteHelper.AsFieldReference(instruction);
+            FieldReference? fieldRef = RewriteHelper.AsFieldReference(instruction);
             if (fieldRef == null || !this.ShouldValidate(fieldRef.DeclaringType))
                 return false;
 
             // skip if not broken
-            FieldDefinition fieldDefinition = fieldRef.Resolve();
+            FieldDefinition? fieldDefinition = fieldRef.Resolve();
             if (fieldDefinition?.HasConstant == false)
                 return false;
 
             // rewrite if possible
-            TypeDefinition declaringType = fieldRef.DeclaringType.Resolve();
+            TypeDefinition? declaringType = fieldRef.DeclaringType.Resolve();
             bool isRead = instruction.OpCode == OpCodes.Ldsfld || instruction.OpCode == OpCodes.Ldfld;
             return
                 this.TryRewriteToProperty(module, instruction, fieldRef, declaringType, isRead)
@@ -56,7 +55,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         *********/
         /// <summary>Whether references to the given type should be validated.</summary>
         /// <param name="type">The type reference.</param>
-        private bool ShouldValidate(TypeReference type)
+        private bool ShouldValidate([NotNullWhen(true)] TypeReference? type)
         {
             return type != null && this.RewriteReferencesToAssemblies.Contains(type.Scope.Name);
         }
@@ -70,8 +69,8 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         private bool TryRewriteToProperty(ModuleDefinition module, Instruction instruction, FieldReference fieldRef, TypeDefinition declaringType, bool isRead)
         {
             // get equivalent property
-            PropertyDefinition property = declaringType?.Properties.FirstOrDefault(p => p.Name == fieldRef.Name);
-            MethodDefinition method = isRead ? property?.GetMethod : property?.SetMethod;
+            PropertyDefinition? property = declaringType?.Properties.FirstOrDefault(p => p.Name == fieldRef.Name);
+            MethodDefinition? method = isRead ? property?.GetMethod : property?.SetMethod;
             if (method == null)
                 return false;
 
@@ -86,14 +85,14 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         /// <summary>Try rewriting the field into a matching const field.</summary>
         /// <param name="instruction">The CIL instruction to rewrite.</param>
         /// <param name="field">The field definition.</param>
-        private bool TryRewriteToConstField(Instruction instruction, FieldDefinition field)
+        private bool TryRewriteToConstField(Instruction instruction, FieldDefinition? field)
         {
             // must have been a static field read, and the new field must be const
             if (instruction.OpCode != OpCodes.Ldsfld || field?.HasConstant != true)
                 return false;
 
             // get opcode for value type
-            Instruction loadInstruction = RewriteHelper.GetLoadValueInstruction(field.Constant);
+            Instruction? loadInstruction = RewriteHelper.GetLoadValueInstruction(field.Constant);
             if (loadInstruction == null)
                 return false;
 
diff --git a/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicMethodRewriter.cs b/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicMethodRewriter.cs
index 4860072c..601ecbbc 100644
--- a/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicMethodRewriter.cs
+++ b/src/SMAPI/Framework/ModLoading/Rewriters/HeuristicMethodRewriter.cs
@@ -1,6 +1,5 @@
-#nullable disable
-
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
@@ -33,7 +32,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         public override bool Handle(ModuleDefinition module, ILProcessor cil, Instruction instruction)
         {
             // get method ref
-            MethodReference methodRef = RewriteHelper.AsMethodReference(instruction);
+            MethodReference? methodRef = RewriteHelper.AsMethodReference(instruction);
             if (methodRef == null || !this.ShouldValidate(methodRef.DeclaringType))
                 return false;
 
@@ -42,13 +41,13 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
                 return false;
 
             // get type
-            var type = methodRef.DeclaringType.Resolve();
+            TypeDefinition? type = methodRef.DeclaringType.Resolve();
             if (type == null)
                 return false;
 
             // get method definition
-            MethodDefinition method = null;
-            foreach (var match in type.Methods.Where(p => p.Name == methodRef.Name))
+            MethodDefinition? method = null;
+            foreach (MethodDefinition match in type.Methods.Where(p => p.Name == methodRef.Name))
             {
                 // reference matches initial parameters of definition
                 if (methodRef.Parameters.Count >= match.Parameters.Count || !this.InitialParametersMatch(methodRef, match))
@@ -72,7 +71,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
                 return false; // SMAPI needs to load the value onto the stack before the method call, but the optional parameter type wasn't recognized
 
             // rewrite method reference
-            foreach (Instruction loadInstruction in loadInstructions)
+            foreach (Instruction? loadInstruction in loadInstructions)
                 cil.InsertBefore(instruction, loadInstruction);
             instruction.Operand = module.ImportReference(method);
 
@@ -86,7 +85,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         *********/
         /// <summary>Whether references to the given type should be validated.</summary>
         /// <param name="type">The type reference.</param>
-        private bool ShouldValidate(TypeReference type)
+        private bool ShouldValidate([NotNullWhen(true)] TypeReference? type)
         {
             return type != null && this.RewriteReferencesToAssemblies.Contains(type.Scope.Name);
         }
diff --git a/src/SMAPI/Framework/ModLoading/Rewriters/MethodParentRewriter.cs b/src/SMAPI/Framework/ModLoading/Rewriters/MethodParentRewriter.cs
index 00daf337..2e2f6316 100644
--- a/src/SMAPI/Framework/ModLoading/Rewriters/MethodParentRewriter.cs
+++ b/src/SMAPI/Framework/ModLoading/Rewriters/MethodParentRewriter.cs
@@ -1,6 +1,5 @@
-#nullable disable
-
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
@@ -28,7 +27,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         /// <param name="fromType">The type whose methods to remap.</param>
         /// <param name="toType">The type with methods to map to.</param>
         /// <param name="nounPhrase">A brief noun phrase indicating what the instruction finder matches (or <c>null</c> to generate one).</param>
-        public MethodParentRewriter(string fromType, Type toType, string nounPhrase = null)
+        public MethodParentRewriter(string fromType, Type toType, string? nounPhrase = null)
             : base(nounPhrase ?? $"{fromType.Split('.').Last()} methods")
         {
             this.FromType = fromType;
@@ -39,14 +38,14 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         /// <param name="fromType">The type whose methods to remap.</param>
         /// <param name="toType">The type with methods to map to.</param>
         /// <param name="nounPhrase">A brief noun phrase indicating what the instruction finder matches (or <c>null</c> to generate one).</param>
-        public MethodParentRewriter(Type fromType, Type toType, string nounPhrase = null)
-            : this(fromType.FullName, toType, nounPhrase) { }
+        public MethodParentRewriter(Type fromType, Type toType, string? nounPhrase = null)
+            : this(fromType.FullName!, toType, nounPhrase) { }
 
         /// <inheritdoc />
         public override bool Handle(ModuleDefinition module, ILProcessor cil, Instruction instruction)
         {
             // get method ref
-            MethodReference methodRef = RewriteHelper.AsMethodReference(instruction);
+            MethodReference? methodRef = RewriteHelper.AsMethodReference(instruction);
             if (!this.IsMatch(methodRef))
                 return false;
 
@@ -61,7 +60,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         *********/
         /// <summary>Get whether a CIL instruction matches.</summary>
         /// <param name="methodRef">The method reference.</param>
-        private bool IsMatch(MethodReference methodRef)
+        private bool IsMatch([NotNullWhen(true)] MethodReference? methodRef)
         {
             return
                 methodRef != null
diff --git a/src/SMAPI/Framework/ModLoading/Rewriters/TypeReferenceRewriter.cs b/src/SMAPI/Framework/ModLoading/Rewriters/TypeReferenceRewriter.cs
index bdc4c4f3..a81cb5be 100644
--- a/src/SMAPI/Framework/ModLoading/Rewriters/TypeReferenceRewriter.cs
+++ b/src/SMAPI/Framework/ModLoading/Rewriters/TypeReferenceRewriter.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using Mono.Cecil;
 using StardewModdingAPI.Framework.ModLoading.Framework;
@@ -19,7 +17,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         private readonly Type ToType;
 
         /// <summary>Get whether a matched type should be ignored.</summary>
-        private readonly Func<TypeReference, bool> ShouldIgnore;
+        private readonly Func<TypeReference, bool>? ShouldIgnore;
 
 
         /*********
@@ -29,7 +27,7 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         /// <param name="fromTypeFullName">The full type name to which to find references.</param>
         /// <param name="toType">The new type to reference.</param>
         /// <param name="shouldIgnore">Get whether a matched type should be ignored.</param>
-        public TypeReferenceRewriter(string fromTypeFullName, Type toType, Func<TypeReference, bool> shouldIgnore = null)
+        public TypeReferenceRewriter(string fromTypeFullName, Type toType, Func<TypeReference, bool>? shouldIgnore = null)
             : base($"{fromTypeFullName} type")
         {
             this.FromTypeName = fromTypeFullName;