Merge pull request github#6520 from smowton/smowton/feature/allow-local-interfaces

Java: Allow local interfaces

Author: smowton

java/change-notes/2021-08-23-local-interfaces-enums.md

@@ -0,0 +1,2 @@
+lgtm,codescanning
+* `Class.isLocal` has been replaced with `ClassOrInterface.isLocal`. This is because as of Java 16, interfaces can be declared method-local. Accordingly, `LocalClassDeclStmt.getLocalClass` is renamed `LocalTypeDeclStmt.getLocalType` and  now returns a `ClassOrInterface`. `BusinessInterface`, declared in `EJB.qll`, has had its `isRemote` and `isLocal` methods renamed `isDeclaredLocal` and `isDeclaredRemote` to avoid a name clash.

java/ql/lib/config/semmlecode.dbscheme

@@ -440,10 +440,10 @@ isAnonymClass(
   int parent: @classinstancexpr ref
 );
 
-#keyset[classid] #keyset[parent]
-isLocalClass(
-  int classid: @class ref,
-  int parent: @localclassdeclstmt ref
+#keyset[typeid] #keyset[parent]
+isLocalClassOrInterface(
+  int typeid: @classorinterface ref,
+  int parent: @localtypedeclstmt ref
 );
 
 isDefConstr(
@@ -526,7 +526,7 @@ case @stmt.kind of
 | 15 = @labeledstmt
 | 16 = @assertstmt
 | 17 = @localvariabledeclstmt
-| 18 = @localclassdeclstmt
+| 18 = @localtypedeclstmt
 | 19 = @constructorinvocationstmt
 | 20 = @superconstructorinvocationstmt
 | 21 = @case

java/ql/lib/config/semmlecode.dbscheme.stats

@@ -169,7 +169,7 @@
 <v>223232</v>
 </e>
 <e>
-<k>@localclassdeclstmt</k>
+<k>@localtypedeclstmt</k>
 <v>349</v>
 </e>
 <e>
@@ -16910,11 +16910,11 @@
 </dependencies>
 </relation>
 <relation>
-<name>isLocalClass</name>
+<name>isLocalClassOrInterface</name>
 <cardinality>349</cardinality>
 <columnsizes>
 <e>
-<k>classid</k>
+<k>typeid</k>
 <v>349</v>
 </e>
 <e>
@@ -16924,7 +16924,7 @@
 </columnsizes>
 <dependencies>
 <dep>
-<src>classid</src>
+<src>typeid</src>
 <trg>parent</trg>
 <val>
 <hist>
@@ -16941,7 +16941,7 @@
 </dep>
 <dep>
 <src>parent</src>
-<trg>classid</trg>
+<trg>typeid</trg>
 <val>
 <hist>
 <budget>12</budget>

java/ql/lib/semmle/code/java/ControlFlowGraph.qll

@@ -456,7 +456,7 @@ private module ControlFlowGraphImpl {
       or
       this instanceof EmptyStmt
       or
-      this instanceof LocalClassDeclStmt
+      this instanceof LocalTypeDeclStmt
       or
       this instanceof AssertStmt
     }

java/ql/lib/semmle/code/java/Member.qll

@@ -40,12 +40,12 @@ class Member extends Element, Annotatable, Modifiable, @member {
 
   /**
    * Gets the immediately enclosing callable, if this member is declared in
-   * an anonymous or local class.
+   * an anonymous or local class or interface.
    */
   Callable getEnclosingCallable() {
-    exists(NestedClass nc | this.getDeclaringType() = nc |
-      nc.(AnonymousClass).getClassInstanceExpr().getEnclosingCallable() = result or
-      nc.(LocalClass).getLocalClassDeclStmt().getEnclosingCallable() = result
+    exists(NestedType nt | this.getDeclaringType() = nt |
+      nt.(AnonymousClass).getClassInstanceExpr().getEnclosingCallable() = result or
+      nt.(LocalClassOrInterface).getLocalTypeDeclStmt().getEnclosingCallable() = result
     )
   }
 }

java/ql/lib/semmle/code/java/PrettyPrintAst.qll

@@ -877,8 +877,8 @@ private class PpLocalVariableDeclStmt extends PpAst, LocalVariableDeclStmt {
   }
 }
 
-private class PpLocalClassDeclStmt extends PpAst, LocalClassDeclStmt {
-  override PpAst getChild(int i) { i = 0 and result = this.getLocalClass() }
+private class PpLocalTypeDeclStmt extends PpAst, LocalTypeDeclStmt {
+  override PpAst getChild(int i) { i = 0 and result = this.getLocalType() }
 }
 
 /*

java/ql/lib/semmle/code/java/PrintAst.qll

@@ -303,19 +303,25 @@ final class ClassInstanceExprNode extends ExprStmtNode {
 }
 
 /**
- * A node representing a `LocalClassDeclStmt`.
+ * A node representing a `LocalTypeDeclStmt`.
  */
-final class LocalClassDeclStmtNode extends ExprStmtNode {
-  LocalClassDeclStmtNode() { element instanceof LocalClassDeclStmt }
+final class LocalTypeDeclStmtNode extends ExprStmtNode {
+  LocalTypeDeclStmtNode() { element instanceof LocalTypeDeclStmt }
 
   override ElementNode getChild(int childIndex) {
     result = super.getChild(childIndex)
     or
     childIndex = 0 and
-    result.getElement() = element.(LocalClassDeclStmt).getLocalClass()
+    result.getElement() = element.(LocalTypeDeclStmt).getLocalType()
   }
 }
 
+/**
+ * DEPRECATED: Renamed `LocalTypeDeclStmtNode` to reflect the fact that
+ * as of Java 16 interfaces can also be declared locally, not just classes.
+ */
+deprecated class LocalClassDeclStmtNode = LocalTypeDeclStmtNode;
+
 /**
  * A node representing a `ForStmt`.
  */

java/ql/lib/semmle/code/java/Statement.qll

@@ -786,20 +786,38 @@ class LocalVariableDeclStmt extends Stmt, @localvariabledeclstmt {
   override string getAPrimaryQlClass() { result = "LocalVariableDeclStmt" }
 }
 
-/** A statement that declares a local class. */
-class LocalClassDeclStmt extends Stmt, @localclassdeclstmt {
-  /** Gets the local class declared by this statement. */
-  LocalClass getLocalClass() { isLocalClass(result, this) }
+/** A statement that declares a local class or interface. */
+class LocalTypeDeclStmt extends Stmt, @localtypedeclstmt {
+  /** Gets the local type declared by this statement. */
+  LocalClassOrInterface getLocalType() { isLocalClassOrInterface(result, this) }
 
-  override string pp() { result = "class " + this.getLocalClass().toString() }
+  /**
+   * DEPRECATED: Renamed `getLocalType` to reflect the fact that
+   * as of Java 16 interfaces can also be declared locally, not just classes.
+   */
+  deprecated LocalClassOrInterface getLocalClass() { result = this.getLocalType() }
+
+  private string getDeclKeyword() {
+    result = "class" and this.getLocalType() instanceof Class
+    or
+    result = "interface" and this.getLocalType() instanceof Interface
+  }
 
-  override string toString() { result = "class ..." }
+  override string pp() { result = this.getDeclKeyword() + " " + this.getLocalType().toString() }
 
-  override string getHalsteadID() { result = "LocalClassDeclStmt" }
+  override string toString() { result = this.getDeclKeyword() + " ..." }
 
-  override string getAPrimaryQlClass() { result = "LocalClassDeclStmt" }
+  override string getHalsteadID() { result = "LocalTypeDeclStmt" }
+
+  override string getAPrimaryQlClass() { result = "LocalTypeDeclStmt" }
 }
 
+/**
+ * DEPRECATED: Renamed `LocalTypeDeclStmt` to reflect the fact that
+ * as of Java 16 interfaces can also be declared locally, not just classes.
+ */
+deprecated class LocalClassDeclStmt = LocalTypeDeclStmt;
+
 /** An explicit `this(...)` constructor invocation. */
 class ThisConstructorInvocationStmt extends Stmt, ConstructorCall, @constructorinvocationstmt {
   /** Gets an argument of this constructor invocation. */

java/ql/lib/semmle/code/java/Type.qll

@@ -6,8 +6,8 @@
  * (`Interface`).
  *
  * Reference types can be at the top level (`TopLevelType`) or nested (`NestedType`).
- * Classes can also be local (`LocalClass`) or anonymous (`AnonymousClass`).
- * Enumerated types (`EnumType`) are a special kind of class.
+ * Classes and interfaces can also be local (`LocalClassOrInterface`, `LocalClass`) or anonymous (`AnonymousClass`).
+ * Enumerated types (`EnumType`) and records (`Record`) are special kinds of classes.
  */
 
 import Member
@@ -269,7 +269,7 @@ predicate declaresMember(Type t, @member m) {
   // Since the type `@member` in the dbscheme includes all `@reftype`s,
   // anonymous and local classes need to be excluded here.
   not m instanceof AnonymousClass and
-  not m instanceof LocalClass
+  not m instanceof LocalClassOrInterface
 }
 
 /**
@@ -608,20 +608,10 @@ class SrcRefType extends RefType {
 }
 
 /** A class declaration. */
-class Class extends RefType, @class {
+class Class extends ClassOrInterface, @class {
   /** Holds if this class is an anonymous class. */
   predicate isAnonymous() { isAnonymClass(this, _) }
 
-  /** Holds if this class is a local class. */
-  predicate isLocal() { isLocalClass(this, _) }
-
-  /** Holds if this class is package protected, that is, neither public nor private nor protected. */
-  predicate isPackageProtected() {
-    not isPrivate() and
-    not isProtected() and
-    not isPublic()
-  }
-
   override RefType getSourceDeclaration() { classes(this, _, _, result) }
 
   /**
@@ -630,11 +620,13 @@ class Class extends RefType, @class {
    * Note that a class may inherit annotations from super-classes.
    */
   override Annotation getAnAnnotation() {
-    result = RefType.super.getAnAnnotation()
+    result = ClassOrInterface.super.getAnAnnotation()
     or
     exists(AnnotationType tp | tp = result.getType() |
       tp.isInherited() and
-      not exists(Annotation ann | ann = RefType.super.getAnAnnotation() | ann.getType() = tp) and
+      not exists(Annotation ann | ann = ClassOrInterface.super.getAnAnnotation() |
+        ann.getType() = tp
+      ) and
       result = this.getASupertype().(Class).getAnAnnotation()
     )
   }
@@ -643,8 +635,6 @@ class Class extends RefType, @class {
 }
 
 /**
- * PREVIEW FEATURE in Java 14. Subject to removal in a future release.
- *
  * A record declaration.
  */
 class Record extends Class {
@@ -727,12 +717,25 @@ class AnonymousClass extends NestedClass {
   override string getAPrimaryQlClass() { result = "AnonymousClass" }
 }
 
-/** A local class. */
-class LocalClass extends NestedClass {
-  LocalClass() { this.isLocal() }
+/** A local class or interface. */
+class LocalClassOrInterface extends NestedType, ClassOrInterface {
+  LocalClassOrInterface() { this.isLocal() }
 
   /** Gets the statement that declares this local class. */
-  LocalClassDeclStmt getLocalClassDeclStmt() { isLocalClass(this, result) }
+  LocalTypeDeclStmt getLocalTypeDeclStmt() { isLocalClassOrInterface(this, result) }
+
+  /**
+   * DEPRECATED: renamed `getLocalTypeDeclStmt` to reflect the fact that
+   * as of Java 16 interfaces can also be declared locally.
+   */
+  deprecated LocalTypeDeclStmt getLocalClassDeclStmt() { result = this.getLocalTypeDeclStmt() }
+
+  override string getAPrimaryQlClass() { result = "LocalClassOrInterface" }
+}
+
+/** A local class. */
+class LocalClass extends LocalClassOrInterface, NestedClass {
+  LocalClass() { this.isLocal() }
 
   override string getAPrimaryQlClass() { result = "LocalClass" }
 }
@@ -842,34 +845,32 @@ class InnerClass extends NestedClass {
   predicate hasEnclosingInstance() {
     // JLS 15.9.2. Determining Enclosing Instances
     not this.(AnonymousClass).getClassInstanceExpr().isInStaticContext() and
-    not this.(LocalClass).getLocalClassDeclStmt().getEnclosingCallable().isStatic()
+    not this.(LocalClass).getLocalTypeDeclStmt().getEnclosingCallable().isStatic()
   }
 }
 
 /** An interface. */
-class Interface extends RefType, @interface {
+class Interface extends ClassOrInterface, @interface {
   override RefType getSourceDeclaration() { interfaces(this, _, _, result) }
 
   override predicate isAbstract() {
     // JLS 9.1.1.1: "Every interface is implicitly abstract"
     any()
   }
 
-  /** Holds if this interface is package protected, that is, neither public nor private nor protected. */
-  predicate isPackageProtected() {
-    not isPrivate() and
-    not isProtected() and
-    not isPublic()
-  }
-
   override string getAPrimaryQlClass() { result = "Interface" }
 }
 
 /** A class or interface. */
-class ClassOrInterface extends RefType {
-  ClassOrInterface() {
-    this instanceof Class or
-    this instanceof Interface
+class ClassOrInterface extends RefType, @classorinterface {
+  /** Holds if this class or interface is local. */
+  predicate isLocal() { isLocalClassOrInterface(this, _) }
+
+  /** Holds if this class or interface is package protected, that is, neither public nor private nor protected. */
+  predicate isPackageProtected() {
+    not isPrivate() and
+    not isProtected() and
+    not isPublic()
   }
 }
 

java/ql/lib/semmle/code/java/dataflow/SSA.qll

@@ -238,7 +238,7 @@ private module SsaImpl {
   /** Gets the definition point of a nested class in the parent scope. */
   private ControlFlowNode parentDef(NestedClass nc) {
     nc.(AnonymousClass).getClassInstanceExpr() = result or
-    nc.(LocalClass).getLocalClassDeclStmt() = result
+    nc.(LocalClass).getLocalTypeDeclStmt() = result
   }
 
   /**