diff --git a/slither/core/declarations/custom_error.py b/slither/core/declarations/custom_error.py
index 9ae6370aef..6a54d61377 100644
--- a/slither/core/declarations/custom_error.py
+++ b/slither/core/declarations/custom_error.py
@@ -42,11 +42,6 @@ def compilation_unit(self) -> "SlitherCompilationUnit":
 
     @staticmethod
     def _convert_type_for_solidity_signature(t: Optional[Union[Type, List[Type]]]):
-        # pylint: disable=import-outside-toplevel
-        from slither.core.declarations import Contract
-
-        if isinstance(t, UserDefinedType) and isinstance(t.type, Contract):
-            return "address"
         return str(t)
 
     @property
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.10-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.10-compact.zip
new file mode 100644
index 0000000000..fc45cb40e2
Binary files /dev/null and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.10-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.11-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.11-compact.zip
new file mode 100644
index 0000000000..853879cf56
Binary files /dev/null and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.11-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.12-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.12-compact.zip
new file mode 100644
index 0000000000..c72629231a
Binary files /dev/null and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.12-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.13-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.13-compact.zip
new file mode 100644
index 0000000000..9ada2c3351
Binary files /dev/null and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.13-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.14-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.14-compact.zip
new file mode 100644
index 0000000000..e36f5b94e5
Binary files /dev/null and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.14-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.15-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.15-compact.zip
new file mode 100644
index 0000000000..1023ab1d45
Binary files /dev/null and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.15-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.4-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.4-compact.zip
index 15e749a197..5ecf2b037a 100644
Binary files a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.4-compact.zip and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.4-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.5-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.5-compact.zip
index 070019e18a..357554c09b 100644
Binary files a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.5-compact.zip and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.5-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.6-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.6-compact.zip
index e99b78ab69..c5f05ef201 100644
Binary files a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.6-compact.zip and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.6-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.7-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.7-compact.zip
index 42062d7081..51828bce7f 100644
Binary files a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.7-compact.zip and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.7-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.8-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.8-compact.zip
index d11a080ffb..eb6ba091b4 100644
Binary files a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.8-compact.zip and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.8-compact.zip differ
diff --git a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.9-compact.zip b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.9-compact.zip
index 1b450a6e3f..17e7520185 100644
Binary files a/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.9-compact.zip and b/tests/ast-parsing/compile/custom_error-0.8.4.sol-0.8.9-compact.zip differ
diff --git a/tests/ast-parsing/custom_error-0.8.4.sol b/tests/ast-parsing/custom_error-0.8.4.sol
index ea185de89e..4e1e388fb1 100644
--- a/tests/ast-parsing/custom_error-0.8.4.sol
+++ b/tests/ast-parsing/custom_error-0.8.4.sol
@@ -52,4 +52,21 @@ contract B is A{
     }
 }
 
+contract ContractArgCustomError {
+    error E(ContractArgCustomError a);
+
+    function f() payable external {
+      g();
+    }
+    
+    function g() private {
+      bool something = h();
+      if (something) {
+        revert E(this);
+      }
+    }
+
+    function h() private returns (bool something) {
+    }
+}
 
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.10-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.10-compact.json
new file mode 100644
index 0000000000..9020c8d522
--- /dev/null
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.10-compact.json
@@ -0,0 +1,23 @@
+{
+  "I": {},
+  "VendingMachine": {
+    "err0()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err1()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err2()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err3()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err4()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "A": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "B": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
+  }
+}
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.11-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.11-compact.json
new file mode 100644
index 0000000000..9020c8d522
--- /dev/null
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.11-compact.json
@@ -0,0 +1,23 @@
+{
+  "I": {},
+  "VendingMachine": {
+    "err0()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err1()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err2()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err3()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err4()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "A": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "B": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
+  }
+}
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.12-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.12-compact.json
new file mode 100644
index 0000000000..9020c8d522
--- /dev/null
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.12-compact.json
@@ -0,0 +1,23 @@
+{
+  "I": {},
+  "VendingMachine": {
+    "err0()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err1()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err2()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err3()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err4()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "A": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "B": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
+  }
+}
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.13-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.13-compact.json
new file mode 100644
index 0000000000..9020c8d522
--- /dev/null
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.13-compact.json
@@ -0,0 +1,23 @@
+{
+  "I": {},
+  "VendingMachine": {
+    "err0()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err1()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err2()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err3()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err4()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "A": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "B": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
+  }
+}
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.14-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.14-compact.json
new file mode 100644
index 0000000000..9020c8d522
--- /dev/null
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.14-compact.json
@@ -0,0 +1,23 @@
+{
+  "I": {},
+  "VendingMachine": {
+    "err0()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err1()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err2()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err3()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err4()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "A": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "B": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
+  }
+}
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.15-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.15-compact.json
new file mode 100644
index 0000000000..9020c8d522
--- /dev/null
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.15-compact.json
@@ -0,0 +1,23 @@
+{
+  "I": {},
+  "VendingMachine": {
+    "err0()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err1()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err2()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n1->2;\n2[label=\"Node Type: EXPRESSION 2\n\"];\n}\n",
+    "err3()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "err4()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "A": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n"
+  },
+  "B": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
+  }
+}
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.4-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.4-compact.json
index 0a90299792..9020c8d522 100644
--- a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.4-compact.json
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.4-compact.json
@@ -14,5 +14,10 @@
     "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
   }
 }
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.5-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.5-compact.json
index 0a90299792..9020c8d522 100644
--- a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.5-compact.json
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.5-compact.json
@@ -14,5 +14,10 @@
     "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
   }
 }
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.6-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.6-compact.json
index 0a90299792..9020c8d522 100644
--- a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.6-compact.json
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.6-compact.json
@@ -14,5 +14,10 @@
     "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
   }
 }
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.7-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.7-compact.json
index 0a90299792..9020c8d522 100644
--- a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.7-compact.json
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.7-compact.json
@@ -14,5 +14,10 @@
     "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
   }
 }
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.8-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.8-compact.json
index 0a90299792..9020c8d522 100644
--- a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.8-compact.json
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.8-compact.json
@@ -14,5 +14,10 @@
     "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
   }
 }
\ No newline at end of file
diff --git a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.9-compact.json b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.9-compact.json
index 0a90299792..9020c8d522 100644
--- a/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.9-compact.json
+++ b/tests/ast-parsing/expected/custom_error-0.8.4.sol-0.8.9-compact.json
@@ -14,5 +14,10 @@
     "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
     "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: RETURN 1\n\"];\n}\n"
+  },
+  "ContractArgCustomError": {
+    "f()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: EXPRESSION 1\n\"];\n}\n",
+    "g()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n0->1;\n1[label=\"Node Type: NEW VARIABLE 1\n\"];\n1->2;\n2[label=\"Node Type: IF 2\n\"];\n2->3[label=\"True\"];\n2->4[label=\"False\"];\n3[label=\"Node Type: EXPRESSION 3\n\"];\n3->4;\n4[label=\"Node Type: END_IF 4\n\"];\n}\n",
+    "h()": "digraph{\n0[label=\"Node Type: ENTRY_POINT 0\n\"];\n}\n"
   }
 }
\ No newline at end of file
diff --git a/tests/test_ast_parsing.py b/tests/test_ast_parsing.py
index 0059713747..506ee3d6bb 100644
--- a/tests/test_ast_parsing.py
+++ b/tests/test_ast_parsing.py
@@ -323,7 +323,7 @@ def make_version(minor: int, patch_min: int, patch_max: int) -> List[str]:
         "custom_error-0.4.0.sol",
         ALL_VERSIONS,
     ),
-    Test("custom_error-0.8.4.sol", make_version(8, 4, 9)),
+    Test("custom_error-0.8.4.sol", make_version(8, 4, 15)),
     Test(
         "top-level-0.4.0.sol",
         VERSIONS_04 + VERSIONS_05 + VERSIONS_06 + ["0.7.0"],