diff --git a/csharp/ql/lib/semmle/code/cil/Declaration.qll b/csharp/ql/lib/semmle/code/cil/Declaration.qll
index 9d35eeba9f9..559703e1707 100644
--- a/csharp/ql/lib/semmle/code/cil/Declaration.qll
+++ b/csharp/ql/lib/semmle/code/cil/Declaration.qll
@@ -5,6 +5,7 @@
 import CIL
 private import dotnet
 private import semmle.code.csharp.Member as CS
+private import semmle.code.csharp.commons.QualifiedName
 
 /**
  * A declaration. Either a member (`Member`) or a variable (`Variable`).
@@ -23,6 +24,14 @@ class Declaration extends DotNet::Declaration, Element, @cil_declaration {
   }
 
   override Declaration getUnboundDeclaration() { result = this }
+
+  override predicate hasQualifiedName(string qualifier, string name) {
+    exists(string dqualifier, string dname |
+      this.getDeclaringType().hasQualifiedName(dqualifier, dname) and
+      qualifier = getQualifiedName(dqualifier, dname)
+    ) and
+    name = this.getName()
+  }
 }
 
 private CS::Declaration toCSharpNonTypeParameter(Declaration d) { result.matchesHandle(d) }
diff --git a/csharp/ql/lib/semmle/code/csharp/Callable.qll b/csharp/ql/lib/semmle/code/csharp/Callable.qll
index 6c9fd828132..20999215d0d 100644
--- a/csharp/ql/lib/semmle/code/csharp/Callable.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Callable.qll
@@ -472,16 +472,6 @@ class Operator extends Callable, Member, Attributable, Overridable, @operator {
   override string toString() { result = Callable.super.toString() }
 
   override Parameter getRawParameter(int i) { result = this.getParameter(i) }
-
-  override predicate hasQualifiedName(string qualifier, string name) {
-    super.hasQualifiedName(qualifier, _) and
-    name = this.getFunctionName()
-  }
-
-  override predicate hasQualifiedName(string namespace, string type, string name) {
-    super.hasQualifiedName(namespace, type, _) and
-    name = this.getFunctionName()
-  }
 }
 
 /** A clone method on a record. */
@@ -1113,14 +1103,6 @@ class LocalFunction extends Callable, Modifiable, Attributable, @local_function
 
   override Callable getEnclosingCallable() { result = this.getStatement().getEnclosingCallable() }
 
-  override predicate hasQualifiedName(string qualifier, string name) {
-    exists(string cqualifier, string type |
-      this.getEnclosingCallable().hasQualifiedName(cqualifier, type) and
-      qualifier = getQualifiedName(cqualifier, type)
-    ) and
-    name = this.getName()
-  }
-
   override Location getALocation() { result = this.getStatement().getALocation() }
 
   override Parameter getRawParameter(int i) { result = this.getParameter(i) }
diff --git a/csharp/ql/lib/semmle/code/csharp/Element.qll b/csharp/ql/lib/semmle/code/csharp/Element.qll
index 390a7b16632..e2f14379472 100644
--- a/csharp/ql/lib/semmle/code/csharp/Element.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Element.qll
@@ -3,9 +3,9 @@
  */
 
 import Location
-import Member
 private import semmle.code.csharp.ExprOrStmtParent
 private import dotnet
+private import commons.QualifiedName
 
 /**
  * A program element. Either a control flow element (`ControlFlowElement`), an
diff --git a/csharp/ql/lib/semmle/code/csharp/Generics.qll b/csharp/ql/lib/semmle/code/csharp/Generics.qll
index ce9c94daaab..82efe78c96d 100644
--- a/csharp/ql/lib/semmle/code/csharp/Generics.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Generics.qll
@@ -101,20 +101,6 @@ private string getTypeArgumentsNames(ConstructedGeneric cg) {
   result = strictconcat(Type t, int i | t = cg.getTypeArgument(i) | t.getName(), "," order by i)
 }
 
-bindingset[t]
-private string getFullName(Type t) {
-  exists(string qualifier, string name |
-    t.hasQualifiedName(qualifier, name) and
-    result = getQualifiedName(qualifier, name)
-  )
-}
-
-/** Gets the concatenation of the `getFullName` of type arguments. */
-language[monotonicAggregates]
-private string getTypeArgumentsQualifiedNames(ConstructedGeneric cg) {
-  result = strictconcat(Type t, int i | t = cg.getTypeArgument(i) | getFullName(t), "," order by i)
-}
-
 /**
  * An unbound generic type. This is a generic type with type parameters
  * (for example `List<T>`) or elided type parameters (for example `List<>`).
@@ -161,19 +147,6 @@ class UnboundGenericType extends ValueOrRefType, UnboundGeneric {
   final override string getName() {
     result = this.getUndecoratedName() + "<" + getTypeParameterCommas(this) + ">"
   }
-
-  final override predicate hasQualifiedName(string qualifier, string name) {
-    exists(string name0 | name = name0 + "<" + getTypeParameterCommas(this) + ">" |
-      exists(string enclosing |
-        this.getDeclaringType().hasQualifiedName(qualifier, enclosing) and
-        name0 = enclosing + "+" + this.getUndecoratedName()
-      )
-      or
-      not exists(this.getDeclaringType()) and
-      qualifier = this.getNamespace().getFullName() and
-      name0 = this.getUndecoratedName()
-    )
-  }
 }
 
 /**
@@ -240,11 +213,6 @@ class TypeParameter extends DotNet::TypeParameter, Type, @type_parameter {
   /** Gets the generic that defines this type parameter. */
   UnboundGeneric getGeneric() { type_parameters(this, _, result, _) }
 
-  final override predicate hasQualifiedName(string qualifier, string name) {
-    qualifier = "" and
-    name = this.getName()
-  }
-
   override string getAPrimaryQlClass() { result = "TypeParameter" }
 }
 
@@ -440,19 +408,6 @@ class ConstructedType extends ValueOrRefType, ConstructedGeneric {
   final override string getName() {
     result = this.getUndecoratedName() + "<" + getTypeArgumentsNames(this) + ">"
   }
-
-  override predicate hasQualifiedName(string qualifier, string name) {
-    exists(string name0 | name = name0 + "<" + getTypeArgumentsQualifiedNames(this) + ">" |
-      exists(string enclosing |
-        this.getDeclaringType().hasQualifiedName(qualifier, enclosing) and
-        name0 = enclosing + "+" + this.getUndecoratedName()
-      )
-      or
-      not exists(this.getDeclaringType()) and
-      qualifier = this.getNamespace().getFullName() and
-      name0 = this.getUndecoratedName()
-    )
-  }
 }
 
 /**
@@ -624,11 +579,6 @@ class ConstructedMethod extends Method, ConstructedGeneric {
     result = this.getUndecoratedName() + "<" + getTypeArgumentsNames(this) + ">"
   }
 
-  override predicate hasQualifiedName(string namespace, string type, string name) {
-    this.getDeclaringType().hasQualifiedName(namespace, type) and
-    name = this.getUndecoratedName() + "<" + getTypeArgumentsQualifiedNames(this) + ">"
-  }
-
   final override string getUndecoratedName() { methods(this, result, _, _, _) }
 }
 
diff --git a/csharp/ql/lib/semmle/code/csharp/Member.qll b/csharp/ql/lib/semmle/code/csharp/Member.qll
index a884f314c15..5c555cbdd88 100644
--- a/csharp/ql/lib/semmle/code/csharp/Member.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Member.qll
@@ -7,6 +7,9 @@ import Variable
 private import dotnet
 private import Implements
 private import TypeRef
+private import commons.QualifiedName
+
+private module QualifiedNameInput implements QualifiedNameInputSig { }
 
 /**
  * A declaration.
@@ -21,6 +24,10 @@ class Declaration extends DotNet::Declaration, Element, @declaration {
 
   override string toString() { result = this.getName() }
 
+  override predicate hasQualifiedName(string qualifier, string name) {
+    QualifiedName<QualifiedNameInput>::hasQualifiedName(this, qualifier, name)
+  }
+
   /**
    * Gets the fully qualified name of this declaration, including types, for example
    * the fully qualified name with types of `M` on line 3 is `N.C.M(int, string)` in
@@ -199,6 +206,10 @@ class Member extends DotNet::Member, Modifiable, @member {
   override predicate isRequired() { Modifiable.super.isRequired() }
 
   override predicate isFile() { Modifiable.super.isFile() }
+
+  final override predicate hasQualifiedName(string namespace, string type, string name) {
+    QualifiedName<QualifiedNameInput>::hasQualifiedName(this, namespace, type, name)
+  }
 }
 
 private class TOverridable = @virtualizable or @callable_accessor;
diff --git a/csharp/ql/lib/semmle/code/csharp/Namespace.qll b/csharp/ql/lib/semmle/code/csharp/Namespace.qll
index 6812eada0a5..f91a9c3c7e6 100644
--- a/csharp/ql/lib/semmle/code/csharp/Namespace.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Namespace.qll
@@ -7,7 +7,7 @@ private import dotnet
 /**
  * A type container. Either a namespace (`Namespace`) or a type (`Type`).
  */
-class TypeContainer extends DotNet::NamedElement, Element, @type_container { }
+class TypeContainer extends Declaration, @type_container { }
 
 /**
  * A namespace, for example
@@ -30,6 +30,10 @@ class Namespace extends DotNet::Namespace, TypeContainer, Declaration, @namespac
     parent_namespace(result, this)
   }
 
+  override predicate hasQualifiedName(string qualifier, string name) {
+    DotNet::Namespace.super.hasQualifiedName(qualifier, name)
+  }
+
   /**
    * Gets a type directly declared in this namespace, if any.
    * For example, the class `File` in
diff --git a/csharp/ql/lib/semmle/code/csharp/Type.qll b/csharp/ql/lib/semmle/code/csharp/Type.qll
index f262688d277..561f6d5338b 100644
--- a/csharp/ql/lib/semmle/code/csharp/Type.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Type.qll
@@ -56,23 +56,6 @@ private predicate isObjectClass(Class c) { c instanceof ObjectType }
  * Either a value type (`ValueType`) or a reference type (`RefType`).
  */
 class ValueOrRefType extends DotNet::ValueOrRefType, Type, Attributable, @value_or_ref_type {
-  /**
-   * Holds if this type has the qualified name `qualifier`.`name`.
-   *
-   * For example the class `System.IO.IOException` has
-   * `qualifier`=`System.IO` and `name`=`IOException`.
-   */
-  override predicate hasQualifiedName(string qualifier, string name) {
-    exists(string enclosing |
-      this.getDeclaringType().hasQualifiedName(qualifier, enclosing) and
-      name = enclosing + "+" + this.getUndecoratedName()
-    )
-    or
-    not exists(this.getDeclaringType()) and
-    qualifier = this.getNamespace().getFullName() and
-    name = this.getUndecoratedName()
-  }
-
   /** Gets the namespace containing this type. */
   Namespace getNamespace() {
     if exists(this.getDeclaringType())
@@ -409,11 +392,6 @@ class NonNestedType extends ValueOrRefType {
  * The `void` type.
  */
 class VoidType extends ValueOrRefType, @void_type {
-  override predicate hasQualifiedName(string qualifier, string name) {
-    qualifier = "System" and
-    name = "Void"
-  }
-
   final override string getName() { result = "Void" }
 
   final override string getUndecoratedName() { result = "Void" }
@@ -1028,11 +1006,6 @@ class NullableType extends ValueType, ConstructedType, @nullable_type {
   override Type getTypeArgument(int p) { p = 0 and result = this.getUnderlyingType() }
 
   override string getAPrimaryQlClass() { result = "NullableType" }
-
-  final override predicate hasQualifiedName(string qualifier, string name) {
-    qualifier = "System" and
-    name = "Nullable<" + this.getUnderlyingType().getQualifiedName() + ">"
-  }
 }
 
 /**
@@ -1102,13 +1075,6 @@ class ArrayType extends DotNet::ArrayType, RefType, @array_type {
     not type_location(this, _) and
     result = this.getElementType().getALocation()
   }
-
-  final override predicate hasQualifiedName(string qualifier, string name) {
-    exists(Type elementType, string name0 |
-      elementType.hasQualifiedName(qualifier, name0) and
-      name = name0 + this.getDimensionString(elementType)
-    )
-  }
 }
 
 /**
@@ -1137,13 +1103,6 @@ class PointerType extends DotNet::PointerType, Type, @pointer_type {
   override string toString() { result = DotNet::PointerType.super.toString() }
 
   override string getAPrimaryQlClass() { result = "PointerType" }
-
-  final override predicate hasQualifiedName(string qualifier, string name) {
-    exists(string name0 |
-      this.getReferentType().hasQualifiedName(qualifier, name0) and
-      name = name0 + "*"
-    )
-  }
 }
 
 /**
@@ -1230,10 +1189,6 @@ class TupleType extends ValueType, @tuple_type {
 
   override Type getChild(int i) { result = this.getUnderlyingType().getChild(i) }
 
-  final override predicate hasQualifiedName(string qualifier, string name) {
-    this.getUnderlyingType().hasQualifiedName(qualifier, name)
-  }
-
   override string getAPrimaryQlClass() { result = "TupleType" }
 }
 
diff --git a/csharp/ql/lib/semmle/code/csharp/Variable.qll b/csharp/ql/lib/semmle/code/csharp/Variable.qll
index 2057ef7da50..be52bcbadaf 100644
--- a/csharp/ql/lib/semmle/code/csharp/Variable.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Variable.qll
@@ -75,8 +75,6 @@ class LocalScopeVariable extends Variable, @local_scope_variable {
    * Holds if this local variable or parameter is `scoped`.
    */
   predicate isScoped() { scoped_annotation(this, _) }
-
-  override predicate hasQualifiedName(string qualifier, string name) { none() }
 }
 
 /**
diff --git a/csharp/ql/lib/semmle/code/csharp/commons/QualifiedName.qll b/csharp/ql/lib/semmle/code/csharp/commons/QualifiedName.qll
index 4955d8db8f2..3c6b2393815 100644
--- a/csharp/ql/lib/semmle/code/csharp/commons/QualifiedName.qll
+++ b/csharp/ql/lib/semmle/code/csharp/commons/QualifiedName.qll
@@ -1,6 +1,201 @@
+/** Provides predicates for working with fully qualified names. */
+
+private import csharp
+private import dotnet
+
 /**
- * Provides predicates related to C# qualified names.
+ * Holds if namespace `n` has the qualified name `qualifier`.`name`.
+ *
+ * For example if the qualified name is `System.Collections.Generic`, then
+ * `qualifier`=`System.Collections` and `name`=`Generic`.
  */
+predicate namespaceHasQualifiedName(DotNet::Namespace n, string qualifier, string name) {
+  if n instanceof DotNet::GlobalNamespace
+  then qualifier = "" and name = ""
+  else (
+    exists(string pqualifier, string pname |
+      namespaceHasQualifiedName(n.getParentNamespace(), pqualifier, pname) and
+      qualifier = getQualifiedName(pqualifier, pname)
+    ) and
+    name = n.getName()
+  )
+}
+
+/** Gets a string of `N` commas where `N + 1` is the number of type parameters of this unbound generic. */
+private string getTypeParameterCommas(UnboundGeneric ug) {
+  result = strictconcat(int i | exists(ug.getTypeParameter(i)) | "", ",")
+}
+
+/** Provides the input to `QualifiedName`. */
+signature module QualifiedNameInputSig {
+  /** Gets the suffix to print after unbound generic `ug`. */
+  default string getUnboundGenericSuffix(UnboundGeneric ug) {
+    result = "<" + getTypeParameterCommas(ug) + ">"
+  }
+}
+
+/** Provides predicates for computing fully qualified names. */
+module QualifiedName<QualifiedNameInputSig Input> {
+  private string getDimensionString(ArrayType at, Type elementType) {
+    exists(Type et, string res |
+      et = at.getElementType() and
+      res = at.getArraySuffix() and
+      if et instanceof ArrayType
+      then result = res + getDimensionString(et, elementType)
+      else (
+        result = res and elementType = et
+      )
+    )
+  }
+
+  bindingset[t]
+  private string getFullName(Type t) {
+    exists(string qualifier, string name |
+      hasQualifiedName(t, qualifier, name) and
+      result = getQualifiedName(qualifier, name)
+    )
+  }
+
+  /** Gets the concatenation of the `getFullName` of type arguments. */
+  language[monotonicAggregates]
+  private string getTypeArgumentsQualifiedNames(ConstructedGeneric cg) {
+    result =
+      strictconcat(Type t, int i | t = cg.getTypeArgument(i) | getFullName(t), "," order by i)
+  }
+
+  /** Holds if declaration `d` has the qualified name `qualifier`.`name`. */
+  predicate hasQualifiedName(Declaration d, string qualifier, string name) {
+    d =
+      any(ValueOrRefType vort |
+        vort instanceof VoidType and
+        qualifier = "System" and
+        name = "Void"
+        or
+        vort =
+          any(ArrayType at |
+            exists(Type elementType, string name0 |
+              hasQualifiedName(elementType, qualifier, name0) and
+              name = name0 + getDimensionString(at, elementType)
+            )
+          )
+        or
+        hasQualifiedName(vort.(TupleType).getUnderlyingType(), qualifier, name)
+        or
+        qualifier = "System" and
+        name = "Nullable<" + getFullName(vort.(NullableType).getUnderlyingType()) + ">"
+        or
+        vort =
+          any(UnboundGenericType ugt |
+            exists(string name0 | name = name0 + Input::getUnboundGenericSuffix(ugt) |
+              exists(string enclosing |
+                hasQualifiedName(ugt.getDeclaringType(), qualifier, enclosing) and
+                name0 = enclosing + "+" + ugt.getUndecoratedName()
+              )
+              or
+              not exists(ugt.getDeclaringType()) and
+              qualifier = ugt.getNamespace().getFullName() and
+              name0 = ugt.getUndecoratedName()
+            )
+          )
+        or
+        vort =
+          any(ConstructedType ct |
+            exists(string name0 | name = name0 + "<" + getTypeArgumentsQualifiedNames(ct) + ">" |
+              exists(string enclosing |
+                hasQualifiedName(ct.getDeclaringType(), qualifier, enclosing) and
+                name0 = enclosing + "+" + ct.getUndecoratedName()
+              )
+              or
+              not exists(ct.getDeclaringType()) and
+              qualifier = ct.getNamespace().getFullName() and
+              name0 = ct.getUndecoratedName()
+            )
+          )
+        or
+        not vort instanceof VoidType and
+        not vort instanceof ArrayType and
+        not vort instanceof TupleType and
+        not vort instanceof NullableType and
+        not vort instanceof UnboundGenericType and
+        not vort instanceof ConstructedType and
+        (
+          exists(string enclosing |
+            hasQualifiedName(vort.getDeclaringType(), qualifier, enclosing) and
+            name = enclosing + "+" + vort.getUndecoratedName()
+          )
+          or
+          not exists(vort.getDeclaringType()) and
+          qualifier = vort.getNamespace().getFullName() and
+          name = vort.getUndecoratedName()
+        )
+      )
+    or
+    exists(string name0 |
+      hasQualifiedName(d.(PointerType).getReferentType(), qualifier, name0) and
+      name = name0 + "*"
+    )
+    or
+    qualifier = "" and
+    name = d.(TypeParameter).getName()
+    or
+    d =
+      any(LocalFunction lf |
+        exists(string cqualifier, string type |
+          hasQualifiedName(lf.getEnclosingCallable(), cqualifier, type) and
+          qualifier = getQualifiedName(cqualifier, type)
+        ) and
+        name = lf.getName()
+      )
+    or
+    // no case for `LocalScopeVariable`
+    namespaceHasQualifiedName(d, qualifier, name)
+    or
+    not d instanceof ValueOrRefType and
+    not d instanceof PointerType and
+    not d instanceof TypeParameter and
+    not d instanceof LocalFunction and
+    not d instanceof LocalScopeVariable and
+    not d instanceof Namespace and
+    exists(string dqualifier, string dname |
+      hasQualifiedName(d.getDeclaringType(), dqualifier, dname) and
+      qualifier = getQualifiedName(dqualifier, dname)
+    ) and
+    (
+      name = d.(Operator).getFunctionName()
+      or
+      not d instanceof Operator and
+      name = d.getName()
+    )
+  }
+
+  /**
+   * Holds if member `m` has name `name` and is defined in type `type`
+   * with namespace `namespace`.
+   */
+  predicate hasQualifiedName(Member m, string namespace, string type, string name) {
+    m =
+      any(ConstructedMethod cm |
+        hasQualifiedName(cm.getDeclaringType(), namespace, type) and
+        name = cm.getUndecoratedName() + "<" + getTypeArgumentsQualifiedNames(cm) + ">"
+      )
+    or
+    m =
+      any(UnboundGenericMethod ugm |
+        hasQualifiedName(ugm.getDeclaringType(), namespace, type) and
+        name = ugm.getUndecoratedName() + Input::getUnboundGenericSuffix(ugm)
+      )
+    or
+    not m instanceof ConstructedMethod and
+    not m instanceof UnboundGenericMethod and
+    hasQualifiedName(m.getDeclaringType(), namespace, type) and
+    (
+      name = m.(Operator).getFunctionName()
+      or
+      not m instanceof Operator and
+      name = m.getName()
+    )
+  }
+}
 
 /**
  * Returns the concatenation of `qualifier` and `name`, separated by a dot.
diff --git a/csharp/ql/lib/semmle/code/dotnet/Declaration.qll b/csharp/ql/lib/semmle/code/dotnet/Declaration.qll
index 573a690c0ec..639ab99c040 100644
--- a/csharp/ql/lib/semmle/code/dotnet/Declaration.qll
+++ b/csharp/ql/lib/semmle/code/dotnet/Declaration.qll
@@ -8,14 +8,6 @@ private import semmle.code.csharp.commons.QualifiedName
 
 /** A declaration. */
 class Declaration extends NamedElement, @dotnet_declaration {
-  override predicate hasQualifiedName(string qualifier, string name) {
-    exists(string dqualifier, string dname |
-      this.getDeclaringType().hasQualifiedName(dqualifier, dname) and
-      qualifier = getQualifiedName(dqualifier, dname)
-    ) and
-    name = this.getName()
-  }
-
   /** Gets the name of this declaration, without additional decoration such as `<...>`. */
   string getUndecoratedName() { none() }
 
diff --git a/csharp/ql/lib/semmle/code/dotnet/Namespace.qll b/csharp/ql/lib/semmle/code/dotnet/Namespace.qll
index 31a625de062..6bf6e3dbc92 100644
--- a/csharp/ql/lib/semmle/code/dotnet/Namespace.qll
+++ b/csharp/ql/lib/semmle/code/dotnet/Namespace.qll
@@ -26,11 +26,7 @@ class Namespace extends Declaration, @namespace {
    * `qualifier`=`System.Collections` and `name`=`Generic`.
    */
   override predicate hasQualifiedName(string qualifier, string name) {
-    exists(string pqualifier, string pname |
-      this.getParentNamespace().hasQualifiedName(pqualifier, pname) and
-      qualifier = getQualifiedName(pqualifier, pname)
-    ) and
-    name = this.getName()
+    namespaceHasQualifiedName(this, qualifier, name)
   }
 
   /** Gets a textual representation of this namespace. */
@@ -51,7 +47,7 @@ class Namespace extends Declaration, @namespace {
    */
   string getFullName() {
     exists(string namespace, string name |
-      this.hasQualifiedName(namespace, name) and
+      namespaceHasQualifiedName(this, namespace, name) and
       result = getQualifiedName(namespace, name)
     )
   }
@@ -60,8 +56,4 @@ class Namespace extends Declaration, @namespace {
 /** The global namespace. */
 class GlobalNamespace extends Namespace {
   GlobalNamespace() { this.getName() = "" }
-
-  override predicate hasQualifiedName(string qualifier, string name) {
-    qualifier = "" and name = ""
-  }
 }