8342090: Infer::IncorporationBinaryOp::equals can produce side-effects

src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java

@@ -3328,6 +3328,10 @@ public Type subst(Type t, List<Type> from, List<Type> to) {
         return t.map(new Subst(from, to));
     }
 
+    /* this class won't substitute all types for example UndetVars are never substituted, this is like this
+     * by design as UndetVars are used locally during inference and shouldn't scape from inference rutines,
+     * some specialized applications could need a tailored solution
+     */
     private class Subst extends StructuralTypeMapping<Void> {
         List<Type> from;
         List<Type> to;
@@ -3359,16 +3363,6 @@ public Type visitTypeVar(TypeVar t, Void ignored) {
             return t;
         }
 
-        @Override
-        public Type visitUndetVar(UndetVar t, Void unused) {
-            for (List<Type> from = this.from, to = this.to; from.nonEmpty(); from = from.tail, to = to.tail) {
-                if (t.equalsIgnoreMetadata(from.head)) {
-                    return to.head;
-                }
-            }
-            return t;
-        }
-
         @Override
         public Type visitClassType(ClassType t, Void ignored) {
             if (!t.isCompound()) {