diff --git a/ql/lib/semmle/go/dataflow/internal/FlowSummaryImpl.qll b/ql/lib/semmle/go/dataflow/internal/FlowSummaryImpl.qll
index f664b7d1..3cd82807 100644
--- a/ql/lib/semmle/go/dataflow/internal/FlowSummaryImpl.qll
+++ b/ql/lib/semmle/go/dataflow/internal/FlowSummaryImpl.qll
@@ -26,9 +26,13 @@ module Public {
     string toString() {
       exists(Content c | this = TContentSummaryComponent(c) and result = c.toString())
       or
-      exists(int i | this = TParameterSummaryComponent(i) and result = "parameter " + i)
+      exists(ArgumentPosition pos |
+        this = TParameterSummaryComponent(pos) and result = "parameter " + pos
+      )
       or
-      exists(int i | this = TArgumentSummaryComponent(i) and result = "argument " + i)
+      exists(ParameterPosition pos |
+        this = TArgumentSummaryComponent(pos) and result = "argument " + pos
+      )
       or
       exists(ReturnKind rk | this = TReturnSummaryComponent(rk) and result = "return (" + rk + ")")
     }
@@ -39,11 +43,11 @@ module Public {
     /** Gets a summary component for content `c`. */
     SummaryComponent content(Content c) { result = TContentSummaryComponent(c) }
 
-    /** Gets a summary component for parameter `i`. */
-    SummaryComponent parameter(int i) { result = TParameterSummaryComponent(i) }
+    /** Gets a summary component for a parameter at position `pos`. */
+    SummaryComponent parameter(ArgumentPosition pos) { result = TParameterSummaryComponent(pos) }
 
-    /** Gets a summary component for argument `i`. */
-    SummaryComponent argument(int i) { result = TArgumentSummaryComponent(i) }
+    /** Gets a summary component for an argument at position `pos`. */
+    SummaryComponent argument(ParameterPosition pos) { result = TArgumentSummaryComponent(pos) }
 
     /** Gets a summary component for a return of kind `rk`. */
     SummaryComponent return(ReturnKind rk) { result = TReturnSummaryComponent(rk) }
@@ -86,7 +90,9 @@ module Public {
     predicate contains(SummaryComponent c) { c = this.drop(_).head() }
 
     /** Gets the bottom element of this stack. */
-    SummaryComponent bottom() { result = this.drop(this.length() - 1).head() }
+    SummaryComponent bottom() {
+      this = TSingletonSummaryComponentStack(result) or result = this.tail().bottom()
+    }
 
     /** Gets a textual representation of this stack. */
     string toString() {
@@ -120,8 +126,10 @@ module Public {
       result = TConsSummaryComponentStack(head, tail)
     }
 
-    /** Gets a singleton stack for argument `i`. */
-    SummaryComponentStack argument(int i) { result = singleton(SummaryComponent::argument(i)) }
+    /** Gets a singleton stack for an argument at position `pos`. */
+    SummaryComponentStack argument(ParameterPosition pos) {
+      result = singleton(SummaryComponent::argument(pos))
+    }
 
     /** Gets a singleton stack representing a return of kind `rk`. */
     SummaryComponentStack return(ReturnKind rk) { result = singleton(SummaryComponent::return(rk)) }
@@ -137,9 +145,15 @@ module Public {
     or
     noComponentSpecificCsv(sc) and
     (
-      exists(int i | sc = TParameterSummaryComponent(i) and result = "Parameter[" + i + "]")
+      exists(ArgumentPosition pos |
+        sc = TParameterSummaryComponent(pos) and
+        result = "Parameter[" + getArgumentPositionCsv(pos) + "]"
+      )
       or
-      exists(int i | sc = TArgumentSummaryComponent(i) and result = "Argument[" + i + "]")
+      exists(ParameterPosition pos |
+        sc = TArgumentSummaryComponent(pos) and
+        result = "Argument[" + getParameterPositionCsv(pos) + "]"
+      )
       or
       sc = TReturnSummaryComponent(getReturnValueKind()) and result = "ReturnValue"
     )
@@ -163,11 +177,11 @@ module Public {
    * A class that exists for QL technical reasons only (the IPA type used
    * to represent component stacks needs to be bounded).
    */
-  abstract class RequiredSummaryComponentStack extends SummaryComponentStack {
+  class RequiredSummaryComponentStack extends Unit {
     /**
      * Holds if the stack obtained by pushing `head` onto `tail` is required.
      */
-    abstract predicate required(SummaryComponent c);
+    abstract predicate required(SummaryComponent head, SummaryComponentStack tail);
   }
 
   /** A callable with a flow summary. */
@@ -201,10 +215,10 @@ module Public {
 
     /**
      * Holds if values stored inside `content` are cleared on objects passed as
-     * the `i`th argument to this callable.
+     * arguments at position `pos` to this callable.
      */
     pragma[nomagic]
-    predicate clearsContent(int i, Content content) { none() }
+    predicate clearsContent(ParameterPosition pos, Content content) { none() }
   }
 }
 
@@ -217,20 +231,20 @@ module Private {
 
   newtype TSummaryComponent =
     TContentSummaryComponent(Content c) or
-    TParameterSummaryComponent(int i) { parameterPosition(i) } or
-    TArgumentSummaryComponent(int i) { parameterPosition(i) } or
+    TParameterSummaryComponent(ArgumentPosition pos) or
+    TArgumentSummaryComponent(ParameterPosition pos) or
     TReturnSummaryComponent(ReturnKind rk)
 
-  private TSummaryComponent thisParam() {
+  private TParameterSummaryComponent thisParam() {
     result = TParameterSummaryComponent(instanceParameterPosition())
   }
 
   newtype TSummaryComponentStack =
     TSingletonSummaryComponentStack(SummaryComponent c) or
     TConsSummaryComponentStack(SummaryComponent head, SummaryComponentStack tail) {
-      tail.(RequiredSummaryComponentStack).required(head)
+      any(RequiredSummaryComponentStack x).required(head, tail)
       or
-      tail.(RequiredSummaryComponentStack).required(TParameterSummaryComponent(_)) and
+      any(RequiredSummaryComponentStack x).required(TParameterSummaryComponent(_), tail) and
       head = thisParam()
       or
       derivedFluentFlowPush(_, _, _, head, tail, _)
@@ -285,9 +299,9 @@ module Private {
 
   /**
    * Holds if `c` has a flow summary from `input` to `arg`, where `arg`
-   * writes to (contents of) the `i`th argument, and `c` has a
-   * value-preserving flow summary from the `i`th argument to a return value
-   * (`return`).
+   * writes to (contents of) arguments at position `pos`, and `c` has a
+   * value-preserving flow summary from the arguments at position `pos`
+   * to a return value (`return`).
    *
    * In such a case, we derive flow from `input` to (contents of) the return
    * value.
@@ -302,10 +316,10 @@ module Private {
     SummarizedCallable c, SummaryComponentStack input, SummaryComponentStack arg,
     SummaryComponentStack return, boolean preservesValue
   ) {
-    exists(int i |
+    exists(ParameterPosition pos |
       summary(c, input, arg, preservesValue) and
-      isContentOfArgument(arg, i) and
-      summary(c, SummaryComponentStack::singleton(TArgumentSummaryComponent(i)), return, true) and
+      isContentOfArgument(arg, pos) and
+      summary(c, SummaryComponentStack::argument(pos), return, true) and
       return.bottom() = TReturnSummaryComponent(_)
     )
   }
@@ -330,10 +344,10 @@ module Private {
     s.head() = TParameterSummaryComponent(_) and exists(s.tail())
   }
 
-  private predicate isContentOfArgument(SummaryComponentStack s, int i) {
-    s.head() = TContentSummaryComponent(_) and isContentOfArgument(s.tail(), i)
+  private predicate isContentOfArgument(SummaryComponentStack s, ParameterPosition pos) {
+    s.head() = TContentSummaryComponent(_) and isContentOfArgument(s.tail(), pos)
     or
-    s = TSingletonSummaryComponentStack(TArgumentSummaryComponent(i))
+    s = SummaryComponentStack::argument(pos)
   }
 
   private predicate outputState(SummarizedCallable c, SummaryComponentStack s) {
@@ -364,8 +378,8 @@ module Private {
   private newtype TSummaryNodeState =
     TSummaryNodeInputState(SummaryComponentStack s) { inputState(_, s) } or
     TSummaryNodeOutputState(SummaryComponentStack s) { outputState(_, s) } or
-    TSummaryNodeClearsContentState(int i, boolean post) {
-      any(SummarizedCallable sc).clearsContent(i, _) and post in [false, true]
+    TSummaryNodeClearsContentState(ParameterPosition pos, boolean post) {
+      any(SummarizedCallable sc).clearsContent(pos, _) and post in [false, true]
     }
 
   /**
@@ -414,21 +428,23 @@ module Private {
         result = "to write: " + s
       )
       or
-      exists(int i, boolean post, string postStr |
-        this = TSummaryNodeClearsContentState(i, post) and
+      exists(ParameterPosition pos, boolean post, string postStr |
+        this = TSummaryNodeClearsContentState(pos, post) and
         (if post = true then postStr = " (post)" else postStr = "") and
-        result = "clear: " + i + postStr
+        result = "clear: " + pos + postStr
       )
     }
   }
 
   /**
-   * Holds if `state` represents having read the `i`th argument for `c`. In this case
-   * we are not synthesizing a data-flow node, but instead assume that a relevant
-   * parameter node already exists.
+   * Holds if `state` represents having read from a parameter at position
+   * `pos` in `c`. In this case we are not synthesizing a data-flow node,
+   * but instead assume that a relevant parameter node already exists.
    */
-  private predicate parameterReadState(SummarizedCallable c, SummaryNodeState state, int i) {
-    state.isInputState(c, SummaryComponentStack::argument(i))
+  private predicate parameterReadState(
+    SummarizedCallable c, SummaryNodeState state, ParameterPosition pos
+  ) {
+    state.isInputState(c, SummaryComponentStack::argument(pos))
   }
 
   /**
@@ -441,9 +457,9 @@ module Private {
     or
     state.isOutputState(c, _)
     or
-    exists(int i |
-      c.clearsContent(i, _) and
-      state = TSummaryNodeClearsContentState(i, _)
+    exists(ParameterPosition pos |
+      c.clearsContent(pos, _) and
+      state = TSummaryNodeClearsContentState(pos, _)
     )
   }
 
@@ -452,9 +468,9 @@ module Private {
     exists(SummaryNodeState state | state.isInputState(c, s) |
       result = summaryNode(c, state)
       or
-      exists(int i |
-        parameterReadState(c, state, i) and
-        result.(ParamNode).isParameterOf(c, i)
+      exists(ParameterPosition pos |
+        parameterReadState(c, state, pos) and
+        result.(ParamNode).isParameterOf(c, pos)
       )
     )
   }
@@ -468,20 +484,20 @@ module Private {
   }
 
   /**
-   * Holds if a write targets `post`, which is a post-update node for the `i`th
-   * parameter of `c`.
+   * Holds if a write targets `post`, which is a post-update node for a
+   * parameter at position `pos` in `c`.
    */
-  private predicate isParameterPostUpdate(Node post, SummarizedCallable c, int i) {
-    post = summaryNodeOutputState(c, SummaryComponentStack::argument(i))
+  private predicate isParameterPostUpdate(Node post, SummarizedCallable c, ParameterPosition pos) {
+    post = summaryNodeOutputState(c, SummaryComponentStack::argument(pos))
   }
 
-  /** Holds if a parameter node is required for the `i`th parameter of `c`. */
-  predicate summaryParameterNodeRange(SummarizedCallable c, int i) {
-    parameterReadState(c, _, i)
+  /** Holds if a parameter node at position `pos` is required for `c`. */
+  predicate summaryParameterNodeRange(SummarizedCallable c, ParameterPosition pos) {
+    parameterReadState(c, _, pos)
     or
-    isParameterPostUpdate(_, c, i)
+    isParameterPostUpdate(_, c, pos)
     or
-    c.clearsContent(i, _)
+    c.clearsContent(pos, _)
   }
 
   private predicate callbackOutput(
@@ -493,10 +509,10 @@ module Private {
   }
 
   private predicate callbackInput(
-    SummarizedCallable c, SummaryComponentStack s, Node receiver, int i
+    SummarizedCallable c, SummaryComponentStack s, Node receiver, ArgumentPosition pos
   ) {
     any(SummaryNodeState state).isOutputState(c, s) and
-    s.head() = TParameterSummaryComponent(i) and
+    s.head() = TParameterSummaryComponent(pos) and
     receiver = summaryNodeInputState(c, s.drop(1))
   }
 
@@ -547,17 +563,17 @@ module Private {
           result = getReturnType(c, rk)
         )
         or
-        exists(int i | head = TParameterSummaryComponent(i) |
+        exists(ArgumentPosition pos | head = TParameterSummaryComponent(pos) |
           result =
             getCallbackParameterType(getNodeType(summaryNodeInputState(pragma[only_bind_out](c),
-                  s.drop(1))), i)
+                  s.drop(1))), pos)
         )
       )
     )
     or
-    exists(SummarizedCallable c, int i, ParamNode p |
-      n = summaryNode(c, TSummaryNodeClearsContentState(i, false)) and
-      p.isParameterOf(c, i) and
+    exists(SummarizedCallable c, ParameterPosition pos, ParamNode p |
+      n = summaryNode(c, TSummaryNodeClearsContentState(pos, false)) and
+      p.isParameterOf(c, pos) and
       result = getNodeType(p)
     )
   }
@@ -571,10 +587,10 @@ module Private {
     )
   }
 
-  /** Holds if summary node `arg` is the `i`th argument of call `c`. */
-  predicate summaryArgumentNode(DataFlowCall c, Node arg, int i) {
+  /** Holds if summary node `arg` is at position `pos` in the call `c`. */
+  predicate summaryArgumentNode(DataFlowCall c, Node arg, ArgumentPosition pos) {
     exists(SummarizedCallable callable, SummaryComponentStack s, Node receiver |
-      callbackInput(callable, s, receiver, i) and
+      callbackInput(callable, s, receiver, pos) and
       arg = summaryNodeOutputState(callable, s) and
       c = summaryDataFlowCall(receiver)
     )
@@ -582,12 +598,12 @@ module Private {
 
   /** Holds if summary node `post` is a post-update node with pre-update node `pre`. */
   predicate summaryPostUpdateNode(Node post, Node pre) {
-    exists(SummarizedCallable c, int i |
-      isParameterPostUpdate(post, c, i) and
-      pre.(ParamNode).isParameterOf(c, i)
+    exists(SummarizedCallable c, ParameterPosition pos |
+      isParameterPostUpdate(post, c, pos) and
+      pre.(ParamNode).isParameterOf(c, pos)
       or
-      pre = summaryNode(c, TSummaryNodeClearsContentState(i, false)) and
-      post = summaryNode(c, TSummaryNodeClearsContentState(i, true))
+      pre = summaryNode(c, TSummaryNodeClearsContentState(pos, false)) and
+      post = summaryNode(c, TSummaryNodeClearsContentState(pos, true))
     )
     or
     exists(SummarizedCallable callable, SummaryComponentStack s |
@@ -610,13 +626,13 @@ module Private {
    * node, and back out to `p`.
    */
   predicate summaryAllowParameterReturnInSelf(ParamNode p) {
-    exists(SummarizedCallable c, int i | p.isParameterOf(c, i) |
-      c.clearsContent(i, _)
+    exists(SummarizedCallable c, ParameterPosition ppos | p.isParameterOf(c, ppos) |
+      c.clearsContent(ppos, _)
       or
       exists(SummaryComponentStack inputContents, SummaryComponentStack outputContents |
         summary(c, inputContents, outputContents, _) and
-        inputContents.bottom() = pragma[only_bind_into](TArgumentSummaryComponent(i)) and
-        outputContents.bottom() = pragma[only_bind_into](TArgumentSummaryComponent(i))
+        inputContents.bottom() = pragma[only_bind_into](TArgumentSummaryComponent(ppos)) and
+        outputContents.bottom() = pragma[only_bind_into](TArgumentSummaryComponent(ppos))
       )
     )
   }
@@ -641,9 +657,9 @@ module Private {
         preservesValue = false and not summary(c, inputContents, outputContents, true)
       )
       or
-      exists(SummarizedCallable c, int i |
-        pred.(ParamNode).isParameterOf(c, i) and
-        succ = summaryNode(c, TSummaryNodeClearsContentState(i, _)) and
+      exists(SummarizedCallable c, ParameterPosition pos |
+        pred.(ParamNode).isParameterOf(c, pos) and
+        succ = summaryNode(c, TSummaryNodeClearsContentState(pos, _)) and
         preservesValue = true
       )
     }
@@ -692,12 +708,20 @@ module Private {
      * node where field `b` is cleared).
      */
     predicate summaryClearsContent(Node n, Content c) {
-      exists(SummarizedCallable sc, int i |
-        n = summaryNode(sc, TSummaryNodeClearsContentState(i, true)) and
-        sc.clearsContent(i, c)
+      exists(SummarizedCallable sc, ParameterPosition pos |
+        n = summaryNode(sc, TSummaryNodeClearsContentState(pos, true)) and
+        sc.clearsContent(pos, c)
       )
     }
 
+    pragma[noinline]
+    private predicate viableParam(
+      DataFlowCall call, SummarizedCallable sc, ParameterPosition ppos, ParamNode p
+    ) {
+      p.isParameterOf(sc, ppos) and
+      sc = viableCallable(call)
+    }
+
     /**
      * Holds if values stored inside content `c` are cleared inside a
      * callable to which `arg` is an argument.
@@ -706,18 +730,25 @@ module Private {
      * `arg` (see comment for `summaryClearsContent`).
      */
     predicate summaryClearsContentArg(ArgNode arg, Content c) {
-      exists(DataFlowCall call, int i |
-        viableCallable(call).(SummarizedCallable).clearsContent(i, c) and
-        arg.argumentOf(call, i)
+      exists(DataFlowCall call, SummarizedCallable sc, ParameterPosition ppos |
+        argumentPositionMatch(call, arg, ppos) and
+        viableParam(call, sc, ppos, _) and
+        sc.clearsContent(ppos, c)
+      )
+    }
+
+    pragma[nomagic]
+    private ParamNode summaryArgParam0(DataFlowCall call, ArgNode arg) {
+      exists(ParameterPosition ppos, SummarizedCallable sc |
+        argumentPositionMatch(call, arg, ppos) and
+        viableParam(call, sc, ppos, result)
       )
     }
 
     pragma[nomagic]
     private ParamNode summaryArgParam(ArgNode arg, ReturnKindExt rk, OutNodeExt out) {
-      exists(DataFlowCall call, int pos, SummarizedCallable callable |
-        arg.argumentOf(call, pos) and
-        viableCallable(call) = callable and
-        result.isParameterOf(callable, pos) and
+      exists(DataFlowCall call |
+        result = summaryArgParam0(call, arg) and
         out = rk.getAnOutNode(call)
       )
     }
@@ -795,39 +826,33 @@ module Private {
     }
 
     /** Holds if specification component `c` parses as parameter `n`. */
-    predicate parseParam(string c, int n) {
+    predicate parseParam(string c, ArgumentPosition pos) {
       specSplit(_, c, _) and
-      (
-        c.regexpCapture("Parameter\\[([-0-9]+)\\]", 1).toInt() = n
-        or
-        exists(int n1, int n2 |
-          c.regexpCapture("Parameter\\[([-0-9]+)\\.\\.([0-9]+)\\]", 1).toInt() = n1 and
-          c.regexpCapture("Parameter\\[([-0-9]+)\\.\\.([0-9]+)\\]", 2).toInt() = n2 and
-          n = [n1 .. n2]
-        )
+      exists(string body |
+        body = c.regexpCapture("Parameter\\[([^\\]]*)\\]", 1) and
+        pos = parseParamBody(body)
       )
     }
 
     /** Holds if specification component `c` parses as argument `n`. */
-    predicate parseArg(string c, int n) {
+    predicate parseArg(string c, ParameterPosition pos) {
       specSplit(_, c, _) and
-      (
-        c.regexpCapture("Argument\\[([-0-9]+)\\]", 1).toInt() = n
-        or
-        exists(int n1, int n2 |
-          c.regexpCapture("Argument\\[([-0-9]+)\\.\\.([0-9]+)\\]", 1).toInt() = n1 and
-          c.regexpCapture("Argument\\[([-0-9]+)\\.\\.([0-9]+)\\]", 2).toInt() = n2 and
-          n = [n1 .. n2]
-        )
+      exists(string body |
+        body = c.regexpCapture("Argument\\[([^\\]]*)\\]", 1) and
+        pos = parseArgBody(body)
       )
     }
 
     private SummaryComponent interpretComponent(string c) {
       specSplit(_, c, _) and
       (
-        exists(int pos | parseArg(c, pos) and result = SummaryComponent::argument(pos))
+        exists(ParameterPosition pos |
+          parseArg(c, pos) and result = SummaryComponent::argument(pos)
+        )
         or
-        exists(int pos | parseParam(c, pos) and result = SummaryComponent::parameter(pos))
+        exists(ArgumentPosition pos |
+          parseParam(c, pos) and result = SummaryComponent::parameter(pos)
+        )
         or
         c = "ReturnValue" and result = SummaryComponent::return(getReturnValueKind())
         or
@@ -867,9 +892,9 @@ module Private {
     }
 
     private class MkStack extends RequiredSummaryComponentStack {
-      MkStack() { interpretSpec(_, _, _, this) }
-
-      override predicate required(SummaryComponent c) { interpretSpec(_, _, c, this) }
+      override predicate required(SummaryComponent head, SummaryComponentStack tail) {
+        interpretSpec(_, _, head, tail)
+      }
     }
 
     private class SummarizedCallableExternal extends SummarizedCallable {
@@ -897,11 +922,13 @@ module Private {
     }
 
     private predicate inputNeedsReference(string c) {
+      c = "Argument" or
       parseArg(c, _) or
       inputNeedsReferenceSpecific(c)
     }
 
     private predicate outputNeedsReference(string c) {
+      c = "Argument" or
       parseArg(c, _) or
       c = "ReturnValue" or
       outputNeedsReferenceSpecific(c)
@@ -934,14 +961,18 @@ module Private {
         interpretOutput(output, idx + 1, ref, mid) and
         specSplit(output, c, idx)
       |
-        exists(int pos |
-          node.asNode().(PostUpdateNode).getPreUpdateNode().(ArgNode).argumentOf(mid.asCall(), pos)
+        exists(ArgumentPosition apos, ParameterPosition ppos |
+          node.asNode().(PostUpdateNode).getPreUpdateNode().(ArgNode).argumentOf(mid.asCall(), apos) and
+          parameterMatch(ppos, apos)
         |
-          parseArg(c, pos)
+          c = "Argument" or parseArg(c, ppos)
         )
         or
-        exists(int pos | node.asNode().(ParamNode).isParameterOf(mid.asCallable(), pos) |
-          c = "Parameter" or parseParam(c, pos)
+        exists(ArgumentPosition apos, ParameterPosition ppos |
+          node.asNode().(ParamNode).isParameterOf(mid.asCallable(), ppos) and
+          parameterMatch(ppos, apos)
+        |
+          c = "Parameter" or parseParam(c, apos)
         )
         or
         c = "ReturnValue" and
@@ -960,7 +991,12 @@ module Private {
         interpretInput(input, idx + 1, ref, mid) and
         specSplit(input, c, idx)
       |
-        exists(int pos | node.asNode().(ArgNode).argumentOf(mid.asCall(), pos) | parseArg(c, pos))
+        exists(ArgumentPosition apos, ParameterPosition ppos |
+          node.asNode().(ArgNode).argumentOf(mid.asCall(), apos) and
+          parameterMatch(ppos, apos)
+        |
+          c = "Argument" or parseArg(c, ppos)
+        )
         or
         exists(ReturnNodeExt ret |
           c = "ReturnValue" and
@@ -1115,9 +1151,9 @@ module Private {
       b.asCall() = summaryDataFlowCall(a.asNode()) and
       value = "receiver"
       or
-      exists(int i |
-        summaryArgumentNode(b.asCall(), a.asNode(), i) and
-        value = "argument (" + i + ")"
+      exists(ArgumentPosition pos |
+        summaryArgumentNode(b.asCall(), a.asNode(), pos) and
+        value = "argument (" + pos + ")"
       )
     }
 
diff --git a/ql/lib/semmle/go/dataflow/internal/FlowSummaryImplSpecific.qll b/ql/lib/semmle/go/dataflow/internal/FlowSummaryImplSpecific.qll
index 915fdbcf..757cb405 100644
--- a/ql/lib/semmle/go/dataflow/internal/FlowSummaryImplSpecific.qll
+++ b/ql/lib/semmle/go/dataflow/internal/FlowSummaryImplSpecific.qll
@@ -22,6 +22,42 @@ predicate parameterPosition(int i) {
 /** Gets the parameter position of the instance parameter. */
 int instanceParameterPosition() { result = -1 }
 
+/** A parameter position represented by an integer. */
+class ParameterPosition extends int {
+  ParameterPosition() {
+    parameterPosition(this)
+  }
+}
+
+/** An argument position represented by an integer. */
+class ArgumentPosition extends int {
+  ArgumentPosition() {
+    parameterPosition(this)
+  }
+}
+
+/** Holds if arguments at position `apos` match parameters at position `ppos`. */
+pragma[inline]
+predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) { ppos = apos }
+
+/**
+ * Holds if `arg` is an argument of `call` with an argument position that matches
+ * parameter position `ppos`.
+ */
+pragma[noinline]
+predicate argumentPositionMatch(DataFlowCall call, ArgNode arg, ParameterPosition ppos) {
+  exists(ArgumentPosition apos |
+    arg.argumentOf(call, apos) and
+    parameterMatch(ppos, apos)
+  )
+}
+
+/** Gets the textual representation of a parameter position in the format used for flow summaries. */
+string getParameterPositionCsv(ParameterPosition pos) { result = pos.toString() }
+
+/** Gets the textual representation of an argument position in the format used for flow summaries. */
+string getArgumentPositionCsv(ArgumentPosition pos) { result = pos.toString() }
+
 Node summaryNode(SummarizedCallable c, SummaryNodeState state) { result = getSummaryNode(c, state) }
 
 /** Gets the synthesized data-flow call for `receiver`. */
@@ -254,3 +290,24 @@ predicate parseReturn(string c, int n) {
     )
   )
 }
+
+bindingset[arg]
+private int parseConstantOrRange(string arg) {
+  result = arg.toInt()
+  or
+  exists(int n1, int n2 |
+    arg.regexpCapture("ReturnValue\\[([-0-9]+)\\.\\.([0-9]+)\\]", 1).toInt() = n1 and
+    arg.regexpCapture("ReturnValue\\[([-0-9]+)\\.\\.([0-9]+)\\]", 2).toInt() = n2 and
+    result = [n1 .. n2]
+  )
+}
+
+bindingset[arg]
+ArgumentPosition parseParamBody(string arg) {
+  result = parseConstantOrRange(arg)
+}
+
+bindingset[arg]
+ParameterPosition parseArgBody(string arg) {
+  result = parseConstantOrRange(arg)
+}