diff --git a/language/src/main/grammars/de/monticore/lang/SysMLExpressions.mc4 b/language/src/main/grammars/de/monticore/lang/SysMLExpressions.mc4
index 91cedf60..6af998ea 100644
--- a/language/src/main/grammars/de/monticore/lang/SysMLExpressions.mc4
+++ b/language/src/main/grammars/de/monticore/lang/SysMLExpressions.mc4
@@ -111,7 +111,7 @@ component grammar SysMLExpressions
    * name of the function to be invoked and an argument list for any remaining arguments (see 7.4.9.4). This is
    * useful for chaining invocations in an effective data flow
    */
-  SysMLFunctionOperationExpression implements Expression =
+  SysMLFunctionOperationExpression implements Expression <291> =
     Expression "->" Name ("(" (SysMLParameter || ",")* ")")? ("{" SysMLElement* inner:Expression "}")? ;
 
   // Eigentlich ist "^" der Name einer CalcDef aus den Domain Libraries
diff --git a/language/src/test/java/parser/ExpressionParserTest.java b/language/src/test/java/parser/ExpressionParserTest.java
index 393d8334..0e64d65f 100644
--- a/language/src/test/java/parser/ExpressionParserTest.java
+++ b/language/src/test/java/parser/ExpressionParserTest.java
@@ -2,6 +2,7 @@
 
 import de.monticore.expressions.commonexpressions._ast.ASTCallExpression;
 import de.monticore.lang.sysmlexpressions._ast.ASTElementOfExpression;
+import de.monticore.lang.sysmlexpressions._ast.ASTSysMLFunctionOperationExpression;
 import de.monticore.lang.sysmlexpressions._ast.ASTSysMLInstantiation;
 import de.monticore.lang.sysmlv2.SysMLv2Mill;
 import de.monticore.lang.sysmlv2._parser.SysMLv2Parser;
@@ -82,4 +83,48 @@ public void testElementOf() throws IOException {
     assertThat(ast.get()).isInstanceOf(ASTElementOfExpression.class);
   }
 
+  /**
+   * Checks if SysMLFunctionOperatorExpressions are parsed without being
+   * wrapped within a Call Expression
+   */
+  @Test
+  public void testSysMLFunctionOperatorExprMinimal() throws IOException {
+    var ast = parser.parse_StringExpression("x->b()");
+
+    assertThat(ast).isPresent();
+    assertThat(Log.getFindings()).isEmpty();
+    // We do expect: SysMLFunctionOperatorExpression with an inner
+    //  expression, name and parameters
+    assertThat(ast.get()).isInstanceOf(ASTSysMLFunctionOperationExpression.class);
+  }
+
+  /**
+   * Checks if SysMLFunctionOperatorExpressions are parsed without being
+   * wrapped within a Call Expression
+   */
+  @Test
+  public void testSysMLFunctionOperatorExpr() throws IOException {
+    var ast = parser.parse_StringExpression("x->excludes(y)");
+
+    assertThat(ast).isPresent();
+    assertThat(Log.getFindings()).isEmpty();
+    // We do expect: SysMLFunctionOperatorExpression with an inner
+    //  expression, name and parameters
+    assertThat(ast.get()).isInstanceOf(ASTSysMLFunctionOperationExpression.class);
+  }
+
+  @Test
+  public void testSysMLFunctionOperatorExpr2() throws IOException {
+    var ast = parser.parse_StringExpression("x->excludes(y.z)");
+
+    assertThat(ast).isPresent();
+    assertThat(Log.getFindings()).isEmpty();
+    // We do expect: SysMLFunctionOperatorExpression with an inner
+    //  expression, name and parameters
+    // currently the parameters are separated in an outer CallExpr
+    assertThat(ast.get()).isInstanceOf(ASTSysMLFunctionOperationExpression.class);
+  }
+
+  // ReachableStates(c.behavior, input2.values())->excludes(SecurityGate_LLR.behavior.Bob_Alice_Eve)
+
 }