Fix compilation of superset operations (dafny-lang#1368)

Fix dafny-lang#1357

Source/Dafny/Compiler.cs

@@ -1070,6 +1070,7 @@ protected virtual void CompileBinOp(BinaryExpr.ResolvedOpcode op,
           e1, e0, tok, resultType,
           out opString, out preOpString, out postOpString, out callString, out staticCallString, out reverseArguments, out truncateResult, out convertE1_to_int,
           errorWr);
+        reverseArguments = !reverseArguments;
       } else if (negatedOp != BinaryExpr.ResolvedOpcode.Add) {  // remember from above that Add stands for "there is no negated op"
         CompileBinOp(negatedOp,
           e0, e1, tok, resultType,

Test/comp/Collections.dfy

@@ -36,6 +36,8 @@ method Sets() {
   print "  disjoint: ", a !! b, " ", b !! c, "\n";
   print "  subset: ", a <= b, " ", b <= c, " ", c <= c, "\n";
   print "  proper subset: ", a < b, " ", b < c, " ", c < c, "\n";
+  print "  superset: ", a >= b, " ", b >= a, " ", c >= c, "\n";
+  print "  proper superset: ", a > b, " ", b > a, " ", c > c, "\n";
   print "  membership: ", 17 in a, " ", 17 in b, " ", 17 in c, "\n";
 
   var cl := new Class;
@@ -75,6 +77,8 @@ method MultiSets() {
   print "  disjoint: ", a !! b, " ", b !! c, "\n";
   print "  subset: ", a <= b, " ", b <= c, " ", c <= c, "\n";
   print "  proper subset: ", a < b, " ", b < c, " ", c < c, "\n";
+  print "  superset: ", a >= b, " ", b >= a, " ", c >= c, "\n";
+  print "  proper superset: ", a > b, " ", b > a, " ", c > c, "\n";
   print "  membership: ", 17 in a, " ", 17 in b, " ", 17 in c, "\n";
   print "  update: ", a[17 := 2], " ", b[17 := 2], " ", c[17 := 2], "\n";
   print "  multiplicity: ", a[17], " ", b[17], " ", c[17], "\n";

Test/comp/Collections.dfy.expect

@@ -10,6 +10,8 @@ Sets: {} {17, 82} {12, 17}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   eq covariance: 1 true true
 false true
@@ -23,6 +25,8 @@ Multisets: multiset{} multiset{17, 17, 82, 82} multiset{12, 17}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   update: multiset{17, 17} multiset{17, 17, 82, 82} multiset{12, 17, 17}
   multiplicity: 0 2 1
@@ -125,6 +129,8 @@ Sets: {} {17, 82} {12, 17}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   eq covariance: 1 true true
 false true
@@ -138,6 +144,8 @@ Multisets: multiset{} multiset{17, 17, 82, 82} multiset{12, 17}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   update: multiset{17, 17} multiset{17, 17, 82, 82} multiset{12, 17, 17}
   multiplicity: 0 2 1
@@ -240,6 +248,8 @@ Sets: {} {17, 82} {12, 17}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   eq covariance: 1 true true
 false true
@@ -253,6 +263,8 @@ Multisets: multiset{} multiset{17, 17, 82, 82} multiset{12, 17}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   update: multiset{17, 17} multiset{17, 17, 82, 82} multiset{12, 17, 17}
   multiplicity: 0 2 1
@@ -355,6 +367,8 @@ Sets: {} {17, 82} {17, 12}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   eq covariance: 1 true true
 false true
@@ -368,6 +382,8 @@ Multisets: multiset{} multiset{17, 17, 82, 82} multiset{17, 12}
   disjoint: true false
   subset: true false true
   proper subset: true false false
+  superset: false true true
+  proper superset: false true false
   membership: false true true
   update: multiset{17, 17} multiset{17, 17, 82, 82} multiset{17, 17, 12}
   multiplicity: 0 2 1