Java: Implement ParameterPosition et al

java/ql/lib/semmle/code/java/dataflow/internal/DataFlowDispatch.qll

@@ -183,6 +183,22 @@ private module DispatchImpl {
       )
     )
   }
+
+  private int parameterPosition() { result in [-1, any(Parameter p).getPosition()] }
+
+  /** A parameter position represented by an integer. */
+  class ParameterPosition extends int {
+    ParameterPosition() { this = parameterPosition() }
+  }
+
+  /** An argument position represented by an integer. */
+  class ArgumentPosition extends int {
+    ArgumentPosition() { this = parameterPosition() }
+  }
+
+  /** Holds if arguments at position `apos` match parameters at position `ppos`. */
+  pragma[inline]
+  predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) { ppos = apos }
 }
 
 import DispatchImpl

java/ql/lib/semmle/code/java/dataflow/internal/DataFlowNodes.qll

@@ -310,6 +310,8 @@ private class ImplicitExprPostUpdate extends ImplicitPostUpdateNode, TImplicitEx
 }
 
 module Private {
+  private import DataFlowDispatch
+
   /** Gets the callable in which this node occurs. */
   DataFlowCallable nodeGetEnclosingCallable(Node n) {
     result.asCallable() = n.asExpr().getEnclosingCallable() or
@@ -324,10 +326,15 @@ module Private {
   }
 
   /** Holds if `p` is a `ParameterNode` of `c` with position `pos`. */
-  predicate isParameterNode(ParameterNode p, DataFlowCallable c, int pos) {
+  predicate isParameterNode(ParameterNode p, DataFlowCallable c, ParameterPosition pos) {
     p.isParameterOf(c.asCallable(), pos)
   }
 
+  /** Holds if `arg` is an `ArgumentNode` of `c` with position `pos`. */
+  predicate isArgumentNode(ArgumentNode arg, DataFlowCall c, ArgumentPosition pos) {
+    arg.argumentOf(c, pos)
+  }
+
   /**
    * A data flow node that occurs as the argument of a call and is passed as-is
    * to the callable. Arguments that are wrapped in an implicit varargs array

java/ql/lib/semmle/code/java/dataflow/internal/FlowSummaryImplSpecific.qll

@@ -3,6 +3,7 @@
  */
 
 private import java
+private import DataFlowDispatch
 private import DataFlowPrivate
 private import DataFlowUtil
 private import FlowSummaryImpl::Private
@@ -13,9 +14,6 @@ private module FlowSummaries {
   private import semmle.code.java.dataflow.FlowSummary as F
 }
 
-/** Holds is `i` is a valid parameter position. */
-predicate parameterPosition(int i) { i in [-1 .. any(Parameter p).getPosition()] }
-
 /** Gets the parameter position of the instance parameter. */
 int instanceParameterPosition() { result = -1 }
 
@@ -189,3 +187,19 @@ predicate interpretInputSpecific(string c, InterpretNode mid, InterpretNode n) {
     n.asNode().asExpr() = fw.getRHS()
   )
 }
+
+/** Gets the argument position obtained by parsing `X` in `Parameter[X]`. */
+bindingset[s]
+ArgumentPosition parseParamBody(string s) {
+  result = s.regexpCapture("([-0-9]+)", 1).toInt()
+  or
+  exists(int n1, int n2 |
+    s.regexpCapture("([-0-9]+)\\.\\.([0-9]+)", 1).toInt() = n1 and
+    s.regexpCapture("([-0-9]+)\\.\\.([0-9]+)", 2).toInt() = n2 and
+    result in [n1 .. n2]
+  )
+}
+
+/** Gets the parameter position obtained by parsing `X` in `Argument[X]`. */
+bindingset[s]
+ParameterPosition parseArgBody(string s) { result = parseParamBody(s) }