diff --git a/cpp/ql/src/semmle/code/cpp/ir/implementation/Opcode.qll b/cpp/ql/src/semmle/code/cpp/ir/implementation/Opcode.qll
index 4e3039b933e..0e4f800bb1b 100644
--- a/cpp/ql/src/semmle/code/cpp/ir/implementation/Opcode.qll
+++ b/cpp/ql/src/semmle/code/cpp/ir/implementation/Opcode.qll
@@ -110,6 +110,8 @@ abstract class RelationalOpcode extends CompareOpcode { }
 
 abstract class CopyOpcode extends Opcode { }
 
+abstract class ConvertToBaseOpcode extends UnaryOpcode { }
+
 abstract class MemoryAccessOpcode extends Opcode { }
 
 abstract class ReturnOpcode extends Opcode { }
@@ -302,11 +304,11 @@ module Opcode {
     final override string toString() { result = "Convert" }
   }
 
-  class ConvertToNonVirtualBase extends UnaryOpcode, TConvertToNonVirtualBase {
+  class ConvertToNonVirtualBase extends ConvertToBaseOpcode, TConvertToNonVirtualBase {
     final override string toString() { result = "ConvertToNonVirtualBase" }
   }
 
-  class ConvertToVirtualBase extends UnaryOpcode, TConvertToVirtualBase {
+  class ConvertToVirtualBase extends ConvertToBaseOpcode, TConvertToVirtualBase {
     final override string toString() { result = "ConvertToVirtualBase" }
   }
 
diff --git a/cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll b/cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll
index 4bdeedf2334..6cc1127c4bd 100644
--- a/cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll
+++ b/cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll
@@ -980,7 +980,15 @@ class InheritanceConversionInstruction extends UnaryInstruction {
  * Represents an instruction that converts from the address of a derived class
  * to the address of a direct non-virtual base class.
  */
-class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToBaseInstruction extends InheritanceConversionInstruction {
+  ConvertToBaseInstruction() { getOpcode() instanceof ConvertToBaseOpcode }
+}
+
+/**
+ * Represents an instruction that converts from the address of a derived class
+ * to the address of a direct non-virtual base class.
+ */
+class ConvertToNonVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToNonVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToNonVirtualBase }
 }
 
@@ -988,7 +996,7 @@ class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstructio
  * Represents an instruction that converts from the address of a derived class
  * to the address of a virtual base class.
  */
-class ConvertToVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToVirtualBase }
 }
 
diff --git a/cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Instruction.qll b/cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Instruction.qll
index 4bdeedf2334..6cc1127c4bd 100644
--- a/cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Instruction.qll
+++ b/cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Instruction.qll
@@ -980,7 +980,15 @@ class InheritanceConversionInstruction extends UnaryInstruction {
  * Represents an instruction that converts from the address of a derived class
  * to the address of a direct non-virtual base class.
  */
-class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToBaseInstruction extends InheritanceConversionInstruction {
+  ConvertToBaseInstruction() { getOpcode() instanceof ConvertToBaseOpcode }
+}
+
+/**
+ * Represents an instruction that converts from the address of a derived class
+ * to the address of a direct non-virtual base class.
+ */
+class ConvertToNonVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToNonVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToNonVirtualBase }
 }
 
@@ -988,7 +996,7 @@ class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstructio
  * Represents an instruction that converts from the address of a derived class
  * to the address of a virtual base class.
  */
-class ConvertToVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToVirtualBase }
 }
 
diff --git a/cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll b/cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll
index 4bdeedf2334..6cc1127c4bd 100644
--- a/cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll
+++ b/cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll
@@ -980,7 +980,15 @@ class InheritanceConversionInstruction extends UnaryInstruction {
  * Represents an instruction that converts from the address of a derived class
  * to the address of a direct non-virtual base class.
  */
-class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToBaseInstruction extends InheritanceConversionInstruction {
+  ConvertToBaseInstruction() { getOpcode() instanceof ConvertToBaseOpcode }
+}
+
+/**
+ * Represents an instruction that converts from the address of a derived class
+ * to the address of a direct non-virtual base class.
+ */
+class ConvertToNonVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToNonVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToNonVirtualBase }
 }
 
@@ -988,7 +996,7 @@ class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstructio
  * Represents an instruction that converts from the address of a derived class
  * to the address of a virtual base class.
  */
-class ConvertToVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToVirtualBase }
 }
 
diff --git a/csharp/ql/src/semmle/code/csharp/ir/implementation/Opcode.qll b/csharp/ql/src/semmle/code/csharp/ir/implementation/Opcode.qll
index 4e3039b933e..0e4f800bb1b 100644
--- a/csharp/ql/src/semmle/code/csharp/ir/implementation/Opcode.qll
+++ b/csharp/ql/src/semmle/code/csharp/ir/implementation/Opcode.qll
@@ -110,6 +110,8 @@ abstract class RelationalOpcode extends CompareOpcode { }
 
 abstract class CopyOpcode extends Opcode { }
 
+abstract class ConvertToBaseOpcode extends UnaryOpcode { }
+
 abstract class MemoryAccessOpcode extends Opcode { }
 
 abstract class ReturnOpcode extends Opcode { }
@@ -302,11 +304,11 @@ module Opcode {
     final override string toString() { result = "Convert" }
   }
 
-  class ConvertToNonVirtualBase extends UnaryOpcode, TConvertToNonVirtualBase {
+  class ConvertToNonVirtualBase extends ConvertToBaseOpcode, TConvertToNonVirtualBase {
     final override string toString() { result = "ConvertToNonVirtualBase" }
   }
 
-  class ConvertToVirtualBase extends UnaryOpcode, TConvertToVirtualBase {
+  class ConvertToVirtualBase extends ConvertToBaseOpcode, TConvertToVirtualBase {
     final override string toString() { result = "ConvertToVirtualBase" }
   }
 
diff --git a/csharp/ql/src/semmle/code/csharp/ir/implementation/raw/Instruction.qll b/csharp/ql/src/semmle/code/csharp/ir/implementation/raw/Instruction.qll
index 4bdeedf2334..6cc1127c4bd 100644
--- a/csharp/ql/src/semmle/code/csharp/ir/implementation/raw/Instruction.qll
+++ b/csharp/ql/src/semmle/code/csharp/ir/implementation/raw/Instruction.qll
@@ -980,7 +980,15 @@ class InheritanceConversionInstruction extends UnaryInstruction {
  * Represents an instruction that converts from the address of a derived class
  * to the address of a direct non-virtual base class.
  */
-class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToBaseInstruction extends InheritanceConversionInstruction {
+  ConvertToBaseInstruction() { getOpcode() instanceof ConvertToBaseOpcode }
+}
+
+/**
+ * Represents an instruction that converts from the address of a derived class
+ * to the address of a direct non-virtual base class.
+ */
+class ConvertToNonVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToNonVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToNonVirtualBase }
 }
 
@@ -988,7 +996,7 @@ class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstructio
  * Represents an instruction that converts from the address of a derived class
  * to the address of a virtual base class.
  */
-class ConvertToVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToVirtualBase }
 }
 
diff --git a/csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/Instruction.qll b/csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/Instruction.qll
index 4bdeedf2334..6cc1127c4bd 100644
--- a/csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/Instruction.qll
+++ b/csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/Instruction.qll
@@ -980,7 +980,15 @@ class InheritanceConversionInstruction extends UnaryInstruction {
  * Represents an instruction that converts from the address of a derived class
  * to the address of a direct non-virtual base class.
  */
-class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToBaseInstruction extends InheritanceConversionInstruction {
+  ConvertToBaseInstruction() { getOpcode() instanceof ConvertToBaseOpcode }
+}
+
+/**
+ * Represents an instruction that converts from the address of a derived class
+ * to the address of a direct non-virtual base class.
+ */
+class ConvertToNonVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToNonVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToNonVirtualBase }
 }
 
@@ -988,7 +996,7 @@ class ConvertToNonVirtualBaseInstruction extends InheritanceConversionInstructio
  * Represents an instruction that converts from the address of a derived class
  * to the address of a virtual base class.
  */
-class ConvertToVirtualBaseInstruction extends InheritanceConversionInstruction {
+class ConvertToVirtualBaseInstruction extends ConvertToBaseInstruction {
   ConvertToVirtualBaseInstruction() { getOpcode() instanceof Opcode::ConvertToVirtualBase }
 }