SafeAttribute supports in properties (#1330)

* SafeAttribute supports in properties

* Update Nep11Token.cs

* Safe setters are not allowed

Author: erikzhang

src/Neo.Compiler.CSharp/ABI/AbiMethod.cs

@@ -28,8 +28,19 @@ public AbiMethod(IMethodSymbol symbol)
             : base(symbol, symbol.GetDisplayName(true), symbol.Parameters.Select(p => p.ToAbiParameter()).ToArray())
         {
             Symbol = symbol;
-            Safe = symbol.GetAttributes().Any(p => p.AttributeClass!.Name == nameof(scfx::Neo.SmartContract.Framework.Attributes.SafeAttribute));
+            Safe = GetSafeAttribute(symbol) != null;
+            if (Safe && symbol.MethodKind == MethodKind.PropertySet)
+                throw new CompilationException(symbol, DiagnosticId.SafeSetter, "Safe setters are not allowed.");
             ReturnType = symbol.ReturnType.GetContractParameterType();
         }
+
+        private static AttributeData? GetSafeAttribute(IMethodSymbol symbol)
+        {
+            AttributeData? attribute = symbol.GetAttributes().FirstOrDefault(p => p.AttributeClass!.Name == nameof(scfx::Neo.SmartContract.Framework.Attributes.SafeAttribute));
+            if (attribute != null) return attribute;
+            if (symbol.AssociatedSymbol is IPropertySymbol property)
+                return property.GetAttributes().FirstOrDefault(p => p.AttributeClass!.Name == nameof(scfx::Neo.SmartContract.Framework.Attributes.SafeAttribute));
+            return null;
+        }
     }
 }

src/Neo.Compiler.CSharp/Diagnostic/DiagnosticId.cs

@@ -39,5 +39,6 @@ static class DiagnosticId
         public const string CapturedStaticFieldNotFound = "NC3007";
         public const string InvalidType = "NC3008";
         public const string InvalidArgument = "NC3009";
+        public const string SafeSetter = "NC3010";
     }
 }

src/Neo.SmartContract.Framework/Attributes/SafeAttribute.cs

@@ -48,7 +48,7 @@ namespace Neo.SmartContract.Framework.Attributes
     /// }
     /// </code>
     /// </remarks>
-    [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
+    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Property, AllowMultiple = false)]
     public class SafeAttribute : Attribute
     {
     }

src/Neo.SmartContract.Framework/Nep11Token.cs

@@ -32,11 +32,8 @@ public abstract class Nep11Token<TokenState> : TokenContract
         protected const byte Prefix_Token = 0x03;
         protected const byte Prefix_AccountToken = 0x04;
 
-        public sealed override byte Decimals
-        {
-            [Safe]
-            get => 0;
-        }
+        [Safe]
+        public sealed override byte Decimals => 0;
 
         [Safe]
         public static UInt160 OwnerOf(ByteString tokenId)

tests/Neo.Compiler.CSharp.TestContracts/Contract_NEP17.cs

@@ -17,7 +17,8 @@ namespace Neo.Compiler.CSharp.TestContracts
     [SupportedStandards(NepStandard.Nep17)]
     public class Contract_NEP17 : Nep17Token
     {
-        public override byte Decimals { [Safe] get => 8; }
+        [Safe]
+        public override byte Decimals => 8;
 
         public override string Symbol { [Safe] get => "TEST"; }
     }