C#: Fix issue with dispatch to implementations of virtual interface members.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/dispatch/Dispatch.qll

@@ -497,9 +497,10 @@ private module Internal {
         result = c.getAnOverrider(t)
       )
       or
-      exists(NonConstructedOverridableCallable c |
+      exists(NonConstructedOverridableCallable c, NonConstructedOverridableCallable mid |
         c = this.getAViableOverrider0() and
-        result = c.getAnOverrider(_)
+        c = mid.getUnboundDeclaration() and
+        result = mid.getAnOverrider(_)
       |
         this.hasUnconstrainedTypeParameterQualifierType()
         or
@@ -1115,8 +1116,7 @@ private module Internal {
 
   /** A call using reflection. */
   private class DispatchReflectionCall extends DispatchReflectionOrDynamicCall,
-    TDispatchReflectionCall
-  {
+    TDispatchReflectionCall {
     override MethodCall getCall() { this = TDispatchReflectionCall(result, _, _, _, _) }
 
     override string getName() { this = TDispatchReflectionCall(_, result, _, _, _) }
@@ -1164,8 +1164,7 @@ private module Internal {
 
   /** A method call using dynamic types. */
   private class DispatchDynamicMethodCall extends DispatchReflectionOrDynamicCall,
-    TDispatchDynamicMethodCall
-  {
+    TDispatchDynamicMethodCall {
     override DynamicMethodCall getCall() { this = TDispatchDynamicMethodCall(result) }
 
     override string getName() { result = this.getCall().getLateBoundTargetName() }
@@ -1186,8 +1185,7 @@ private module Internal {
 
   /** An operator call using dynamic types. */
   private class DispatchDynamicOperatorCall extends DispatchReflectionOrDynamicCall,
-    TDispatchDynamicOperatorCall
-  {
+    TDispatchDynamicOperatorCall {
     override DynamicOperatorCall getCall() { this = TDispatchDynamicOperatorCall(result) }
 
     override string getName() {
@@ -1204,8 +1202,7 @@ private module Internal {
 
   /** A (potential) call to a property accessor using dynamic types. */
   private class DispatchDynamicMemberAccess extends DispatchReflectionOrDynamicCall,
-    TDispatchDynamicMemberAccess
-  {
+    TDispatchDynamicMemberAccess {
     override DynamicMemberAccess getCall() { this = TDispatchDynamicMemberAccess(result) }
 
     override string getName() {
@@ -1229,8 +1226,7 @@ private module Internal {
 
   /** A (potential) call to an indexer accessor using dynamic types. */
   private class DispatchDynamicElementAccess extends DispatchReflectionOrDynamicCall,
-    TDispatchDynamicElementAccess
-  {
+    TDispatchDynamicElementAccess {
     override DynamicElementAccess getCall() { this = TDispatchDynamicElementAccess(result) }
 
     override string getName() {
@@ -1256,8 +1252,7 @@ private module Internal {
 
   /** A (potential) call to an event accessor using dynamic types. */
   private class DispatchDynamicEventAccess extends DispatchReflectionOrDynamicCall,
-    TDispatchDynamicEventAccess
-  {
+    TDispatchDynamicEventAccess {
     override AssignArithmeticOperation getCall() {
       this = TDispatchDynamicEventAccess(result, _, _)
     }
@@ -1274,8 +1269,7 @@ private module Internal {
 
   /** A call to a constructor using dynamic types. */
   private class DispatchDynamicObjectCreation extends DispatchReflectionOrDynamicCall,
-    TDispatchDynamicObjectCreation
-  {
+    TDispatchDynamicObjectCreation {
     override DynamicObjectCreation getCall() { this = TDispatchDynamicObjectCreation(result) }
 
     override string getName() { none() }