Java: Fix some performance issues.

Author: aschackmull

java/ql/src/Likely Bugs/Collections/IteratorRemoveMayFail.ql

@@ -30,7 +30,7 @@ predicate containsSpecialCollection(Expr e, SpecialCollectionCreation origin) {
   e = origin
   or
   exists(Variable v |
-    containsSpecialCollection(v.getAnAssignedValue(), origin) and
+    containsSpecialCollection(pragma[only_bind_into](v.getAnAssignedValue()), origin) and
     e = v.getAnAccess()
   )
   or
@@ -52,7 +52,7 @@ predicate iterOfSpecialCollection(Expr e, SpecialCollectionCreation origin) {
   )
   or
   exists(Variable v |
-    iterOfSpecialCollection(v.getAnAssignedValue(), origin) and
+    iterOfSpecialCollection(pragma[only_bind_into](v.getAnAssignedValue()), origin) and
     e = v.getAnAccess()
   )
   or

java/ql/src/Likely Bugs/Comparison/StringComparison.ql

@@ -41,17 +41,21 @@ class StringValue extends Expr {
   }
 }
 
-predicate variableValuesInterned(Variable v) {
+predicate candidateVariable(Variable v) {
   v.fromSource() and
-  // All assignments to variables are interned.
-  forall(StringValue sv | sv = v.getAnAssignedValue() | sv.isInterned()) and
   // For parameters, assume they could be non-interned.
   not v instanceof Parameter and
   // If the string is modified with `+=`, then the new string is not interned
   // even if the components are.
   not exists(AssignOp append | append.getDest() = v.getAnAccess())
 }
 
+predicate variableValuesInterned(Variable v) {
+  candidateVariable(v) and
+  // All assignments to variables are interned.
+  forall(StringValue sv | sv = v.getAnAssignedValue() | sv.isInterned())
+}
+
 from EqualityTest e, StringValue lhs, StringValue rhs
 where
   e.getLeftOperand() = lhs and

java/ql/src/Performance/InnerClassCouldBeStatic.ql

@@ -17,6 +17,7 @@ import java
  * since package-protected fields are not inherited by classes in different
  * packages, but it's enough for the purposes of this check.
  */
+pragma[nomagic]
 predicate inherits(Class c, Field f) {
   f = c.getAField()
   or