Java: Add InstanceOfExpr.getCheckedType()

Additionally change `EqualsUsesInstanceOf.ql` to check for all RefTypes
instead of only Class.

Author: Marcono1234

java/ql/src/Language Abuse/DubiousTypeTestOfThis.ql

@@ -17,7 +17,7 @@ from InstanceOfExpr ioe, RefType t, RefType ct
 where
   ioe.getExpr() instanceof ThisAccess and
   t = ioe.getExpr().getType() and
-  ct = ioe.getTypeName().getType() and
+  ct = ioe.getCheckedType() and
   ct.getASupertype*() = t
 select ioe,
   "Testing whether 'this' is an instance of $@ in $@ introduces a dependency cycle between the two types.",

java/ql/src/Language Abuse/UselessTypeTest.ql

@@ -15,7 +15,7 @@ import java
 from InstanceOfExpr ioe, RefType t, RefType ct
 where
   t = ioe.getExpr().getType() and
-  ct = ioe.getTypeName().getType() and
+  ct = ioe.getCheckedType() and
   ct = t.getASupertype+()
 select ioe,
   "There is no need to test whether an instance of $@ is also an instance of $@ - it always is.", t,

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

@@ -17,8 +17,8 @@ predicate instanceofInEquals(EqualsMethod m, InstanceOfExpr e) {
   m.fromSource() and
   e.getEnclosingCallable() = m and
   e.getExpr().(VarAccess).getVariable() = m.getParameter() and
-  exists(Class instanceofType |
-    instanceofType = e.getTypeName().getType() and
+  exists(RefType instanceofType |
+    instanceofType = e.getCheckedType() and
     not instanceofType.isFinal()
   )
 }

java/ql/src/Likely Bugs/Likely Typos/ContradictoryTypeChecks.ql

@@ -18,7 +18,7 @@ import semmle.code.java.dataflow.SSA
 /** `ioe` is of the form `va instanceof t`. */
 predicate instanceOfCheck(InstanceOfExpr ioe, VarAccess va, RefType t) {
   ioe.getExpr() = va and
-  ioe.getTypeName().getType().(RefType).getSourceDeclaration() = t
+  ioe.getCheckedType().getSourceDeclaration() = t
 }
 
 /** Expression `e` assumes that `va` could be of type `t`. */

java/ql/src/Violations of Best Practice/Implementation Hiding/AbstractToConcreteCollection.ql

@@ -16,9 +16,9 @@ import java
 import semmle.code.java.Collections
 
 predicate guardedByInstanceOf(VarAccess e, RefType t) {
-  exists(IfStmt s, InstanceOfExpr instanceCheck, Type checkType |
+  exists(IfStmt s, InstanceOfExpr instanceCheck, RefType checkType |
     s.getCondition() = instanceCheck and
-    instanceCheck.getTypeName().getType() = checkType and
+    instanceCheck.getCheckedType() = checkType and
     // The same variable appears as the subject of the `instanceof`.
     instanceCheck.getExpr() = e.getVariable().getAnAccess() and
     // The checked type is either the type itself, or a raw version. For example, it is usually

java/ql/src/semmle/code/java/Dependency.qll

@@ -76,7 +76,7 @@ predicate depends(RefType t, RefType dep) {
     or
     // the type accessed in an `instanceof` expression in `t`.
     exists(InstanceOfExpr ioe | t = ioe.getEnclosingCallable().getDeclaringType() |
-      usesType(ioe.getTypeName().getType(), dep)
+      usesType(ioe.getCheckedType(), dep)
     )
   )
 }

java/ql/src/semmle/code/java/DependencyCounts.qll

@@ -100,7 +100,7 @@ predicate numDepends(RefType t, RefType dep, int value) {
         elem = ioe and
         t = ioe.getEnclosingCallable().getDeclaringType()
       |
-        usesType(ioe.getTypeName().getType(), dep)
+        usesType(ioe.getCheckedType(), dep)
       )
     )
 }

java/ql/src/semmle/code/java/Expr.qll

@@ -1333,6 +1333,9 @@ class InstanceOfExpr extends Expr, @instanceofexpr {
   /** Gets the access to the type on the right-hand side of the `instanceof` operator. */
   Expr getTypeName() { result.isNthChildOf(this, 1) }
 
+  /** Gets the type this `instanceof` expression checks for. */
+  RefType getCheckedType() { result = getTypeName().getType() }
+
   /** Gets a printable representation of this expression. */
   override string toString() { result = "...instanceof..." }
 

java/ql/src/semmle/code/java/dataflow/NullGuards.qll

@@ -25,8 +25,8 @@ Expr enumConstEquality(Expr e, boolean polarity, EnumConstant c) {
 }
 
 /** Gets an instanceof expression of `v` with type `type` */
-InstanceOfExpr instanceofExpr(SsaVariable v, Type type) {
-  result.getTypeName().getType() = type and
+InstanceOfExpr instanceofExpr(SsaVariable v, RefType type) {
+  result.getCheckedType() = type and
   result.getExpr() = v.getAUse()
 }
 

java/ql/src/semmle/code/java/dataflow/Nullness.qll

@@ -504,7 +504,7 @@ private predicate correlatedConditions(
       inverted = pol1.booleanXor(pol2)
     )
     or
-    exists(SsaVariable v, Type type |
+    exists(SsaVariable v, RefType type |
       cond1.getCondition() = instanceofExpr(v, type) and
       cond2.getCondition() = instanceofExpr(v, type) and
       inverted = false