diff --git a/javascript/ql/src/Declarations/UnreachableMethodOverloads.ql b/javascript/ql/src/Declarations/UnreachableMethodOverloads.ql
index a68617ea2f1..912d58ab54c 100644
--- a/javascript/ql/src/Declarations/UnreachableMethodOverloads.ql
+++ b/javascript/ql/src/Declarations/UnreachableMethodOverloads.ql
@@ -45,20 +45,22 @@ string getKind(MemberDeclaration m) {
 /**
  * A call-signature that originates from a MethodSignature in the AST.
  */
-private class MethodCallSig extends CallSignatureType {
-  string name;
+private class MethodCallSig extends Function {
+  private MethodSignature signature;
 
-  MethodCallSig() {
-    exists(MethodSignature sig |
-      this = sig.getBody().getCallSignature() and
-      name = sig.getName()
-    )
+  MethodCallSig() { this = signature.getBody() }
+
+  int getNumOptionalParameter() {
+    result = count(Parameter p | p = this.getParameter(_) and p.isDeclaredOptional())
   }
 
-  /**
-   * Gets the name of any member that has this signature.
-   */
-  string getName() { result = name }
+  int getNumRequiredParameter() {
+    result = count(Parameter p | p = this.getParameter(_) and not p.isDeclaredOptional())
+  }
+
+  SignatureKind getKind() { result = SignatureKind::function() }
+
+  TypeExpr getTypeParameterBound(int i) { result = this.getTypeParameter(i).getBound() }
 }
 
 pragma[noinline]
@@ -75,6 +77,7 @@ private MethodCallSig getMethodCallSigWithFingerprint(
 /**
  * Holds if the two call signatures could be overloads of each other and have the same parameter types.
  */
+pragma[inline]
 predicate matchingCallSignature(MethodCallSig method, MethodCallSig other) {
   other =
     getMethodCallSigWithFingerprint(method.getName(), method.getNumOptionalParameter(),
@@ -109,6 +112,16 @@ private MethodSignature getMethodSignatureWithFingerprint(
   result.getBody().getNumParameter() = numParameters
 }
 
+bindingset[t1, t2]
+pragma[inline_late]
+private predicate sameType(TypeExpr t1, TypeExpr t2) {
+  t1.(PredefinedTypeExpr).getName() = t2.(PredefinedTypeExpr).getName()
+  or
+  t1 instanceof ThisTypeExpr and t2 instanceof ThisTypeExpr
+  or
+  t1.(LocalTypeAccess).getLocalTypeName() = t2.(LocalTypeAccess).getLocalTypeName()
+}
+
 /**
  * Holds if the two method signatures are overloads of each other and have the same parameter types.
  */
@@ -122,14 +135,13 @@ predicate signaturesMatch(MethodSignature method, MethodSignature other) {
     not exists(method.getBody().getThisTypeAnnotation()) and
     not exists(other.getBody().getThisTypeAnnotation())
     or
-    method.getBody().getThisTypeAnnotation().getType() =
-      other.getBody().getThisTypeAnnotation().getType()
+    sameType(method.getBody().getThisTypeAnnotation(), other.getBody().getThisTypeAnnotation())
   ) and
   // The types are compared in matchingCallSignature. This is a consistency check that the textual representation of the type-annotations are somewhat similar.
   forall(int i | i in [0 .. -1 + method.getBody().getNumParameter()] |
     getParameterTypeAnnotation(method, i) = getParameterTypeAnnotation(other, i)
   ) and
-  matchingCallSignature(method.getBody().getCallSignature(), other.getBody().getCallSignature())
+  matchingCallSignature(method.getBody(), other.getBody())
 }
 
 from ClassOrInterface decl, string name, MethodSignature previous, MethodSignature unreachable
diff --git a/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/UnreachableMethodOverloads.expected b/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/UnreachableMethodOverloads.expected
index 44bd568e767..24767950a66 100644
--- a/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/UnreachableMethodOverloads.expected
+++ b/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/UnreachableMethodOverloads.expected
@@ -1,5 +1,2 @@
-| tst.ts:3:3:3:30 | method( ... number; | This overload of method() is unreachable, the $@ overload will always be selected. | tst.ts:2:3:2:30 | method( ... string; | previous |
 | tst.ts:6:3:6:17 | types1(): any[] | This overload of types1() is unreachable, the $@ overload will always be selected. | tst.ts:5:3:5:18 | types1<T>(): T[] | previous |
-| tst.ts:15:3:15:74 | on(even ... nction; | This overload of on() is unreachable, the $@ overload will always be selected. | tst.ts:14:3:14:74 | on(even ... nction; | previous |
 | tst.ts:21:3:21:28 | bar(thi ... number; | This overload of bar() is unreachable, the $@ overload will always be selected. | tst.ts:20:3:20:28 | bar(thi ... string; | previous |
-| tst.ts:27:3:27:30 | method( ... number; | This overload of method() is unreachable, the $@ overload will always be selected. | tst.ts:26:3:26:30 | method( ... string; | previous |
diff --git a/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/tst.ts b/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/tst.ts
index 17d95f835cf..4ffd64bc7c1 100644
--- a/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/tst.ts
+++ b/javascript/ql/test/query-tests/Declarations/UnreachableOverloads/tst.ts
@@ -1,6 +1,6 @@
 declare class Foobar {
   method(foo: number): string;
-  method(foo: number): number; // $ Alert
+  method(foo: number): number; // $ MISSING: Alert
 
   types1<T>(): T[]
   types1(): any[] // $ Alert
@@ -12,7 +12,7 @@ declare class Foobar {
   types3<T extends string>(t: T): number
 
   on(event: string, fn?: (event?: any, ...args: any[]) => void): Function;
-  on(event: string, fn?: (event?: any, ...args: any[]) => void): Function; // $ Alert
+  on(event: string, fn?: (event?: any, ...args: any[]) => void): Function; // $ MISSING: Alert
 
   foo(this: string): string;
   foo(this: number): number;
@@ -24,7 +24,7 @@ declare class Foobar {
 
 declare class Base {
   method(foo: number): string;
-  method(foo: number): number; // $ Alert
+  method(foo: number): number; // $ MISSING: Alert
 
   overRiddenInSub(): string;
   overRiddenInSub(): number;