Java: Don't inherit methods from co-/contra-variant supertypes.

aschackmull · aschackmull · commit 411891c30315 · 2018-11-13T14:56:22.000+01:00
diff --git a/java/ql/src/semmle/code/java/Type.qll b/java/ql/src/semmle/code/java/Type.qll
@@ -435,22 +435,6 @@ class RefType extends Type, Annotatable, Modifiable, @reftype {
     hasInterfaceMethod(m, declaringType) and hidden = false
   }
 
-  private predicate noMethodExtraction() {
-    not methods(_, _, _, _, this, _) and
-    exists(Method m | methods(m, _, _, _, getSourceDeclaration(), _) and m.isInheritable())
-  }
-
-  private predicate canInheritFromSupertype(RefType sup) {
-    sup = getASupertype() and
-    (noMethodExtraction() implies supertypeSrcDecl(sup, getSourceDeclaration()))
-  }
-
-  pragma[nomagic]
-  private predicate supertypeSrcDecl(RefType sup, RefType srcDecl) {
-    sup = getASupertype() and
-    srcDecl = sup.getSourceDeclaration()
-  }
-
   private predicate hasNonInterfaceMethod(Method m, RefType declaringType, boolean hidden) {
     m = getAMethod() and
     this = declaringType and
@@ -464,7 +448,7 @@ class RefType extends Type, Annotatable, Modifiable, @reftype {
         else h1 = false
       ) and
       (not sup instanceof Interface or this instanceof Interface) and
-      canInheritFromSupertype(sup) and
+      this.extendsOrImplements(sup) and
       sup.hasNonInterfaceMethod(m, declaringType, h2) and
       hidden = h1.booleanOr(h2) and
       exists(string signature |
@@ -491,7 +475,7 @@ class RefType extends Type, Annotatable, Modifiable, @reftype {
     exists(RefType sup |
       sup.interfaceMethodCandidateWithSignature(m, signature, declaringType) and
       not cannotInheritInterfaceMethod(signature) and
-      canInheritFromSupertype(sup) and
+      this.extendsOrImplements(sup) and
       m.isInheritable()
     )
   }
diff --git a/java/ql/test/query-tests/Naming/ConfusingOverloading.expected b/java/ql/test/query-tests/Naming/ConfusingOverloading.expected
@@ -1 +1 @@
-| NamingTest.java:4:17:4:22 | equals | Method NamingTest.equals(..) could be confused with overloaded method $@, since dispatch depends on static types. | NamingTest.java:3:17:3:22 | equals | equals |
+| NamingTest.java:7:17:7:22 | equals | Method NamingTest.equals(..) could be confused with overloaded method $@, since dispatch depends on static types. | NamingTest.java:6:17:6:22 | equals | equals |
diff --git a/java/ql/test/query-tests/Naming/NamingTest.java b/java/ql/test/query-tests/Naming/NamingTest.java
@@ -1,8 +1,19 @@
+import java.util.*;
+import java.util.function.*;
+import java.util.stream.*;
 
 public class NamingTest {
 	public boolean equals(Object other) { return false; }
 	public boolean equals(NamingTest other) { return true; }
-	
+
 	public void visit(Object node) {}
 	public void visit(NamingTest t) {}
+
+	public class Elem<T> {}
+
+	public Object get(List<Elem<String>> lll) {
+		Predicate<?> p = null;
+		p.test(null);
+		return lll.stream().map(l -> l).filter(Objects::nonNull).collect(Collectors.toList());
+	}
 }

Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-\| NamingTest.java:4:17:4:22 \| equals \| Method NamingTest.equals(..) could be confused with overloaded method $@, since dispatch depends on static types. \| NamingTest.java:3:17:3:22 \| equals \| equals \|`
	`1`	`+\| NamingTest.java:7:17:7:22 \| equals \| Method NamingTest.equals(..) could be confused with overloaded method $@, since dispatch depends on static types. \| NamingTest.java:6:17:6:22 \| equals \| equals \|`