reduce duplicate codes

Author: smdn

src/Smdn.Fundamental.Reflection/Smdn.Reflection.Attributes/ICustomAttributeProviderExtensions.cs

@@ -29,4 +29,14 @@ internal static bool HasCompilerGeneratedAttribute(this ICustomAttributeProvider
           StringComparison.Ordinal
         )
       );
+
+  internal static bool HasIsReadOnlyAttribute(this ICustomAttributeProvider attributeProvider)
+    => GetCustomAttributeDataList(attributeProvider)
+      .Any(static d =>
+        string.Equals(
+          d.AttributeType.FullName,
+          "System.Runtime.CompilerServices.IsReadOnlyAttribute",
+          StringComparison.Ordinal
+        )
+      );
 }

src/Smdn.Fundamental.Reflection/Smdn.Reflection/FieldInfoExtensions.cs

@@ -4,7 +4,6 @@
 #if NULL_STATE_STATIC_ANALYSIS_ATTRIBUTES
 using System.Diagnostics.CodeAnalysis;
 #endif
-using System.Linq;
 using System.Reflection;
 
 using Smdn.Reflection.Attributes;
@@ -103,7 +102,5 @@ backingField.DeclaringType is null
   public static bool IsReadOnly(this FieldInfo f)
     => f is null
       ? throw new ArgumentNullException(nameof(f))
-      : f.GetCustomAttributesData().Any(
-          static d => string.Equals(d.AttributeType.FullName, "System.Runtime.CompilerServices.IsReadOnlyAttribute", StringComparison.Ordinal)
-        );
+      : f.HasIsReadOnlyAttribute();
 }

src/Smdn.Fundamental.Reflection/Smdn.Reflection/MethodInfoExtensions.cs

@@ -8,6 +8,8 @@
 using System.Reflection;
 using System.Runtime.CompilerServices;
 
+using Smdn.Reflection.Attributes;
+
 namespace Smdn.Reflection;
 
 public static class MethodInfoExtensions {
@@ -198,7 +200,5 @@ internal static bool SignatureEqual(MethodInfo x, MethodInfo y)
   public static bool IsReadOnly(this MethodInfo m)
     => m is null
       ? throw new ArgumentNullException(nameof(m))
-      : m.GetCustomAttributesData().Any(
-          static d => string.Equals(d.AttributeType.FullName, "System.Runtime.CompilerServices.IsReadOnlyAttribute", StringComparison.Ordinal)
-        );
+      : m.HasIsReadOnlyAttribute();
 }

src/Smdn.Fundamental.Reflection/Smdn.Reflection/TypeExtensions.cs

@@ -6,6 +6,8 @@
 using System.Reflection;
 using System.Runtime.InteropServices;
 
+using Smdn.Reflection.Attributes;
+
 namespace Smdn.Reflection;
 
 public static class TypeExtensions {
@@ -77,9 +79,7 @@ public static bool IsEnumFlags(this Type t)
   public static bool IsReadOnlyValueType(this Type t)
     =>
       ROCType.IsValueType(t ?? throw new ArgumentNullException(nameof(t))) &&
-      t.GetCustomAttributesData().Any(
-        static d => string.Equals(d.AttributeType.FullName, "System.Runtime.CompilerServices.IsReadOnlyAttribute", StringComparison.Ordinal)
-      );
+      t.HasIsReadOnlyAttribute();
 
   public static bool IsByRefLikeValueType(this Type t)
     =>