[NF] Fix when-branch cref set check.

- Use lists instead of AVL trees for the sets, since the order of
  insertion changes the structure of the trees such that structural
  equality can't be used for the check.
- Remove BaseAvlSet.isEqual, it's no longer needed and might be
  misleading due to only checking structural equality.

Belonging to [master]:
  - #3009
  - OpenModelica/OpenModelica-testsuite#1150

Author: perost

Compiler/NFFrontEnd/NFComponentRef.mo

@@ -568,6 +568,18 @@ public
     end match;
   end isEqual;
 
+  function isLess
+    input ComponentRef cref1;
+    input ComponentRef cref2;
+    output Boolean isLess = compare(cref1, cref2) < 0;
+  end isLess;
+
+  function isGreater
+    input ComponentRef cref1;
+    input ComponentRef cref2;
+    output Boolean isGreater = compare(cref1, cref2) > 0;
+  end isGreater;
+
   function isPrefix
     input ComponentRef cref1;
     input ComponentRef cref2;

Compiler/NFFrontEnd/NFVerifyModel.mo

@@ -35,7 +35,6 @@ encapsulated uniontype NFVerifyModel
 protected
   import List;
   import Error;
-  import BaseAvlSet;
   import DAE;
   import ElementSource;
   import ExecStat.execStat;
@@ -55,26 +54,6 @@ public
   end verify;
 
 protected
-  type CrefSet = CrefSetImpl.Tree;
-
-  encapsulated package CrefSetImpl
-    import BaseAvlSet;
-    import ComponentRef = NFComponentRef;
-    extends BaseAvlSet;
-
-    redeclare type Key = ComponentRef;
-
-    redeclare function extends keyStr
-    algorithm
-      outString := ComponentRef.toString(inKey);
-    end keyStr;
-
-    redeclare function extends keyCompare
-    algorithm
-      outResult := ComponentRef.compare(inKey1, inKey2);
-    end keyCompare;
-  end CrefSetImpl;
-
   function verifyEquation
     input Equation eq;
   algorithm
@@ -94,7 +73,7 @@ protected
     input list<Equation.Branch> branches;
     input DAE.ElementSource source;
   protected
-    CrefSet crefs1, crefs2;
+    list<ComponentRef> crefs1, crefs2;
     list<Equation.Branch> rest_branches;
     list<Equation> body;
   algorithm
@@ -110,7 +89,7 @@ protected
       Equation.Branch.BRANCH(body = body) := branch;
       crefs2 := whenEquationBranchCrefs(body);
 
-      if not CrefSet.isEqual(crefs1, crefs2) then
+      if not List.isEqualOnTrue(crefs1, crefs2, ComponentRef.isEqual) then
         Error.addSourceMessage(Error.DIFFERENT_VARIABLES_SOLVED_IN_ELSEWHEN,
           {}, ElementSource.getInfo(source));
         fail();
@@ -122,24 +101,25 @@ protected
     "Helper function to verifyWhenEquation, returns the set of crefs that the
      given list of equations contains on the lhs."
     input list<Equation> eql;
-    output CrefSet crefs;
+    output list<ComponentRef> crefs = {};
   algorithm
-    crefs := CrefSet.new();
-
     for eq in eql loop
       crefs := match eq
         case Equation.EQUALITY() then whenEquationEqualityCrefs(eq.lhs, crefs);
         case Equation.IF()       then whenEquationIfCrefs(eq.branches, eq.source, crefs);
       end match;
     end for;
+
+    crefs := List.sort(crefs, ComponentRef.isGreater);
+    crefs := List.sortedUnique(crefs, ComponentRef.isEqual);
   end whenEquationBranchCrefs;
 
   function whenEquationEqualityCrefs
     input Expression lhsExp;
-    input output CrefSet crefs;
+    input output list<ComponentRef> crefs;
   algorithm
     crefs := match lhsExp
-      case Expression.CREF() then CrefSet.add(crefs, lhsExp.cref);
+      case Expression.CREF() then lhsExp.cref :: crefs;
       case Expression.TUPLE()
         then List.fold(lhsExp.elements, whenEquationEqualityCrefs, crefs);
     end match;
@@ -150,9 +130,9 @@ protected
      of the same set of crefs, and adds that set to the given set of crefs."
     input list<Equation.Branch> branches;
     input DAE.ElementSource source;
-    input output CrefSet crefs;
+    input output list<ComponentRef> crefs;
   protected
-    CrefSet crefs1, crefs2;
+    list<ComponentRef> crefs1, crefs2;
     list<Equation.Branch> rest_branches;
     list<Equation> body;
   algorithm
@@ -164,14 +144,14 @@ protected
       crefs2 := whenEquationBranchCrefs(body);
 
       // All the branches must have the same set of crefs on the lhs.
-      if not CrefSet.isEqual(crefs1, crefs2) then
+      if not List.isEqualOnTrue(crefs1, crefs2, ComponentRef.isEqual) then
         Error.addSourceMessage(Error.WHEN_IF_VARIABLE_MISMATCH,
           {}, ElementSource.getInfo(source));
         fail();
       end if;
     end for;
 
-    crefs := CrefSet.join(crefs, crefs1);
+    crefs := listAppend(crefs1, crefs);
   end whenEquationIfCrefs;
 
   annotation(__OpenModelica_Interface="frontend");

Compiler/Util/BaseAvlSet.mo

@@ -175,25 +175,6 @@ algorithm
   end match;
 end isEmpty;
 
-function isEqual
-  input Tree tree1;
-  input Tree tree2;
-  output Boolean isEqual;
-algorithm
-  isEqual := match (tree1, tree2)
-    case (NODE(), NODE())
-      then tree1.height == tree2.height and
-           keyCompare(tree1.key, tree2.key) == 0 and
-           isEqual(tree1.left, tree2.left) and
-           isEqual(tree1.right, tree2.right);
-
-    case (LEAF(), LEAF())
-      then keyCompare(tree1.key, tree2.key) == 0;
-
-    else true;
-  end match;
-end isEqual;
-
 function listKeys
   "Converts the tree to a flat list of keys (in order)."
   input Tree inTree;