C#: Move isLiveOutRefParameterDefinition to top-level.

csharp/ql/lib/semmle/code/csharp/dataflow/SSA.qll

@@ -190,6 +190,8 @@ module Ssa {
     )
   }
 
+  predicate isLiveOutRefParameterDefinition = SsaImpl::isLiveOutRefParameterDefinition/2;
+
   /**
    * A static single assignment (SSA) definition. Either an explicit variable
    * definition (`ExplicitDefinition`), an implicit variable definition
@@ -408,10 +410,12 @@ module Ssa {
     }
 
     /**
+     * DEPRECATED: Use `isLiveOutRefParameterDefinition(SsaDefinition, Parameter)` instead.
+     *
      * Holds if this SSA definition assigns to `out`/`ref` parameter `p`, and the
      * parameter may remain unchanged throughout the rest of the enclosing callable.
      */
-    final predicate isLiveOutRefParameterDefinition(Parameter p) {
+    deprecated final predicate isLiveOutRefParameterDefinition(Parameter p) {
       SsaImpl::isLiveOutRefParameterDefinition(this, p)
     }
 

csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll

@@ -1244,7 +1244,7 @@ class SsaNode extends NodeImpl, TSsaNode {
 class SsaDefinitionNode extends SsaNode {
   override SsaImpl::DataFlowIntegration::SsaDefinitionNode node;
 
-  Ssa::Definition getDefinition() { result = node.getDefinition() }
+  SsaDefinition getDefinition() { result = node.getDefinition() }
 
   override ControlFlowNode getControlFlowNodeImpl() {
     result = this.getDefinition().getControlFlowNode()
@@ -1613,7 +1613,7 @@ private module ReturnNodes {
 
     OutRefReturnNode() {
       exists(Parameter p |
-        this.getDefinition().isLiveOutRefParameterDefinition(p) and
+        Ssa::isLiveOutRefParameterDefinition(this.getDefinition(), p) and
         kind.getPosition() = p.getPosition()
       |
         p.isOut() and kind instanceof OutReturnKind

csharp/ql/lib/semmle/code/csharp/dataflow/internal/SsaImpl.qll

@@ -914,6 +914,10 @@ private module Cached {
     Impl::uncertainWriteDefinitionInput(def, result)
   }
 
+  /**
+   * Holds if the SSA definition `def` assigns to `out`/`ref` parameter `p`, and the
+   * parameter may remain unchanged throughout the rest of the enclosing callable.
+   */
   cached
   predicate isLiveOutRefParameterDefinition(SsaDefinition def, Parameter p) {
     p.isOutOrRef() and

csharp/ql/test/library-tests/dataflow/callablereturnsarg/Common.qll

@@ -5,7 +5,7 @@ private predicate outRefDef(DataFlow::ExprNode ne, int outRef) {
   exists(Ssa::ExplicitDefinition def, Parameter outRefParameter |
     outRefParameter.isOutOrRef() and
     ne.getExpr() = def.getADefinition().getSource() and
-    def.isLiveOutRefParameterDefinition(outRefParameter) and
+    Ssa::isLiveOutRefParameterDefinition(def, outRefParameter) and
     outRef = outRefParameter.getPosition()
   )
 }

csharp/ql/test/library-tests/dataflow/ssa/IsLiveOutRefParameterDefinition.ql

@@ -1,7 +1,7 @@
 import csharp
 
-from Ssa::SourceVariable v, Ssa::Definition def
+from Ssa::SourceVariable v, SsaDefinition def
 where
   v = def.getSourceVariable() and
-  def.isLiveOutRefParameterDefinition(_)
+  Ssa::isLiveOutRefParameterDefinition(def, _)
 select v, def