diff --git a/grammars/csharp.tmLanguage b/grammars/csharp.tmLanguage
index 39475fd..25fb7b4 100644
--- a/grammars/csharp.tmLanguage
+++ b/grammars/csharp.tmLanguage
@@ -227,6 +227,10 @@
             <key>include</key>
             <string>#comment</string>
           </dict>
+          <dict>
+            <key>include</key>
+            <string>#storage-modifier</string>
+          </dict>
           <dict>
             <key>include</key>
             <string>#property-declaration</string>
@@ -243,6 +247,10 @@
             <key>include</key>
             <string>#method-declaration</string>
           </dict>
+          <dict>
+            <key>include</key>
+            <string>#operator-declaration</string>
+          </dict>
           <dict>
             <key>include</key>
             <string>#attribute-section</string>
diff --git a/grammars/csharp.tmLanguage.cson b/grammars/csharp.tmLanguage.cson
index 653818f..e61aaf8 100644
--- a/grammars/csharp.tmLanguage.cson
+++ b/grammars/csharp.tmLanguage.cson
@@ -156,6 +156,9 @@ repository:
       {
         include: "#comment"
       }
+      {
+        include: "#storage-modifier"
+      }
       {
         include: "#property-declaration"
       }
@@ -168,6 +171,9 @@ repository:
       {
         include: "#method-declaration"
       }
+      {
+        include: "#operator-declaration"
+      }
       {
         include: "#attribute-section"
       }
diff --git a/src/csharp.tmLanguage.yml b/src/csharp.tmLanguage.yml
index 194bbd8..fe43f6b 100644
--- a/src/csharp.tmLanguage.yml
+++ b/src/csharp.tmLanguage.yml
@@ -69,10 +69,12 @@ repository:
     patterns:
     - include: '#preprocessor'
     - include: '#comment'
+    - include: '#storage-modifier'
     - include: '#property-declaration'
     - include: '#event-declaration'
     - include: '#indexer-declaration'
     - include: '#method-declaration'
+    - include: '#operator-declaration'
     - include: '#attribute-section'
     - include: '#punctuation-semicolon'
 
diff --git a/test/interface.tests.ts b/test/interface.tests.ts
index 26a2f95..afdbdd5 100644
--- a/test/interface.tests.ts
+++ b/test/interface.tests.ts
@@ -100,5 +100,79 @@ interface IBar : IFoo { }
                 Token.Punctuation.OpenBrace,
                 Token.Punctuation.CloseBrace]);
         });
+
+        it("generic interface with abstract methods (issue #307)", async () => {
+
+            const input = `
+public interface IAdditionSubtraction<T> where T : IAdditionSubtraction<T>
+{
+    public abstract static T operator -(T left, T right);
+    abstract static T operator +(T left, T right);
+    public abstract void M();
+    void N();
+}`;
+            const tokens = await tokenize(input);
+
+            tokens.should.deep.equal([
+                Token.Keyword.Modifier.Public,
+                Token.Keyword.Definition.Interface,
+                Token.Identifier.InterfaceName("IAdditionSubtraction"),
+                Token.Punctuation.TypeParameter.Begin,
+                Token.Identifier.TypeParameterName("T"),
+                Token.Punctuation.TypeParameter.End,
+                Token.Keyword.Modifier.Where,
+                Token.Identifier.TypeParameterName("T"),
+                Token.Punctuation.Colon,
+                Token.Type("IAdditionSubtraction"),
+                Token.Punctuation.TypeParameter.Begin,
+                Token.Type("T"),
+                Token.Punctuation.TypeParameter.End,
+                Token.Punctuation.OpenBrace,
+
+                Token.Keyword.Modifier.Public,
+                Token.Keyword.Modifier.Abstract,
+                Token.Keyword.Modifier.Static,
+                Token.Type("T"),
+                Token.Keyword.Definition.Operator,
+                Token.Identifier.MethodName("-"),
+                Token.Punctuation.OpenParen,
+                Token.Type("T"),
+                Token.Identifier.ParameterName("left"),
+                Token.Punctuation.Comma,
+                Token.Type("T"),
+                Token.Identifier.ParameterName("right"),
+                Token.Punctuation.CloseParen,
+                Token.Punctuation.Semicolon,
+
+                Token.Keyword.Modifier.Abstract,
+                Token.Keyword.Modifier.Static,
+                Token.Type("T"),
+                Token.Keyword.Definition.Operator,
+                Token.Identifier.MethodName("+"),
+                Token.Punctuation.OpenParen,
+                Token.Type("T"),
+                Token.Identifier.ParameterName("left"),
+                Token.Punctuation.Comma,
+                Token.Type("T"),
+                Token.Identifier.ParameterName("right"),
+                Token.Punctuation.CloseParen,
+                Token.Punctuation.Semicolon,
+
+                Token.Keyword.Modifier.Public,
+                Token.Keyword.Modifier.Abstract,
+                Token.PrimitiveType.Void,
+                Token.Identifier.MethodName("M"),
+                Token.Punctuation.OpenParen,
+                Token.Punctuation.CloseParen,
+                Token.Punctuation.Semicolon,
+
+                Token.PrimitiveType.Void,
+                Token.Identifier.MethodName("N"),
+                Token.Punctuation.OpenParen,
+                Token.Punctuation.CloseParen,
+                Token.Punctuation.Semicolon,
+
+                Token.Punctuation.CloseBrace]);
+        });
     });
 });