Address review comments

Author: hvitved

rust/ql/lib/codeql/rust/dataflow/internal/Node.qll

@@ -230,7 +230,7 @@ final class ExprArgumentNode extends ArgumentNode, ExprNode {
   ExprArgumentNode() {
     isArgumentForCall(n, call_, pos_) and
     not TypeInference::implicitDeref(n) and
-    not TypeInference::implicitBorrow(n)
+    not TypeInference::implicitBorrow(n, _)
   }
 
   override predicate isArgumentOf(DataFlowCall call, RustDataFlow::ArgumentPosition pos) {
@@ -579,7 +579,7 @@ newtype TNode =
     TypeInference::implicitDeref(n) and
     borrow = false
     or
-    TypeInference::implicitBorrow(n) and
+    TypeInference::implicitBorrow(n, _) and
     borrow = true
   } or
   TDerefOutNode(DerefExpr de, Boolean isPost) or

rust/ql/lib/codeql/rust/internal/Type.qll

@@ -226,31 +226,28 @@ TypeParamTypeParameter getArrayTypeParameter() {
 
 abstract class RefType extends StructType { }
 
-pragma[nomagic]
-TypeParamTypeParameter getRefTypeParameter() {
-  result = any(RefType t).getPositionalTypeParameter(0)
-}
-
 class RefMutType extends RefType {
   RefMutType() { this.getStruct() instanceof Builtins::RefMutType }
 
   override string toString() { result = "&mut" }
 }
 
-pragma[nomagic]
-TypeParamTypeParameter getRefMutTypeParameter() {
-  result = any(RefMutType t).getPositionalTypeParameter(0)
-}
-
 class RefSharedType extends RefType {
   RefSharedType() { this.getStruct() instanceof Builtins::RefSharedType }
 
   override string toString() { result = "&" }
 }
 
 pragma[nomagic]
-TypeParamTypeParameter getRefSharedTypeParameter() {
-  result = any(RefSharedType t).getPositionalTypeParameter(0)
+RefType getRefType(boolean isMutable) {
+  isMutable = true and result instanceof RefMutType
+  or
+  isMutable = false and result instanceof RefSharedType
+}
+
+pragma[nomagic]
+TypeParamTypeParameter getRefTypeParameter(boolean isMutable) {
+  result = getRefType(isMutable).getPositionalTypeParameter(0)
 }
 
 /**