C++: Delete confusing class synonym.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll

@@ -2292,7 +2292,7 @@ class ContentSet instanceof Content {
 
 pragma[nomagic]
 private predicate guardControlsPhiInput(
-  IRGuardCondition g, boolean branch, Ssa::Definition def, IRBlock input, Ssa::PhiNode phi
+  IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input, Ssa::PhiNode phi
 ) {
   phi.hasInputFromBlock(def, _, _, _, input) and
   (

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll

@@ -1059,7 +1059,7 @@ module SsaCached {
   }
 
   cached
-  Definition phiHasInputFromBlockExt(PhiNode phi, IRBlock bb) {
+  DefinitionExt phiHasInputFromBlockExt(PhiNode phi, IRBlock bb) {
     SsaImpl::phiHasInputFromBlockExt(phi, result, bb)
   }
 
@@ -1116,12 +1116,12 @@ class PhiNode extends SsaImpl::DefinitionExt {
   }
 
   /** Gets a definition that is an input to this phi node. */
-  final Definition getAnInput() { this.hasInputFromBlock(result, _, _, _, _) }
+  final DefinitionExt getAnInput() { this.hasInputFromBlock(result, _, _, _, _) }
 }
 
 /** An static single assignment (SSA) definition. */
 class DefinitionExt extends SsaImpl::DefinitionExt {
-  private Definition getAPhiInputOrPriorDefinition() { result = this.(PhiNode).getAnInput() }
+  private DefinitionExt getAPhiInputOrPriorDefinition() { result = this.(PhiNode).getAnInput() }
 
   /**
    * Gets a definition that ultimately defines this SSA definition and is
@@ -1182,6 +1182,4 @@ class DefinitionExt extends SsaImpl::DefinitionExt {
   }
 }
 
-class Definition = SsaImpl::Definition;
-
 import SsaCached