Package org.checkerframework.checker.interning

Class InterningVisitor

java.lang.Object

com.sun.source.util.TreeScanner<R,P>

com.sun.source.util.TreePathScanner<R,P>

org.checkerframework.framework.source.SourceVisitor<Void,Void>

org.checkerframework.common.basetype.BaseTypeVisitor<InterningAnnotatedTypeFactory>

org.checkerframework.checker.interning.InterningVisitor

All Implemented Interfaces:

TreeVisitor<Void,Void>

public final class InterningVisitor
extends BaseTypeVisitor<InterningAnnotatedTypeFactory>

Typechecks source code for interning violations. A type is considered interned if its primary annotation is Interned or InternedDistinct. This visitor reports errors or warnings for violations for the following cases:

1. either argument to a "==" or "!=" comparison is not Interned (error "not.interned"). As a special case, the comparison is permitted if either arugment is InternedDistinct.
2. the receiver and argument for a call to an equals method are both Interned (optional warning "unnecessary.equals")

See Also:

• BaseTypeVisitor

Nested Class Summary

Nested classes/interfaces inherited from class org.checkerframework.common.basetype.BaseTypeVisitor

BaseTypeVisitor.OverrideChecker

Field Summary

Fields inherited from class org.checkerframework.common.basetype.BaseTypeVisitor

atypeFactory, checker, DETERMINISTIC, IMPURE, methodTree, positions, PURE, qualHierarchy, showchecks, SIDE_EFFECT_FREE, TARGET, targetValueElement, typeHierarchy, typeValidator, unusedWhenElement

Fields inherited from class org.checkerframework.framework.source.SourceVisitor

elements, root, trees, treesWithSuppressWarnings, types

Constructor Summary

Constructors

Constructor	Description
InterningVisitor(BaseTypeChecker checker)	Create an InterningVisitor.

Method Summary

Modifier and Type	Method	Description
protected void	checkConstructorResult(AnnotatedTypeMirror.AnnotatedExecutableType constructorType, ExecutableElement constructorElement)	Issue a warning if the result type of the constructor declaration is not top.
static boolean	isInvocationOfEquals(MethodInvocationTree tree)	Tests whether a method invocation is an invocation of Object.equals(java.lang.Object) with one argument.
protected boolean	isTypeCastSafe(AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType)	Returns true if the cast is safe.
void	processClassTree(ClassTree classTree)	Method to implement the @UsesObjectEquals functionality.
boolean	validateTypeOf(Tree tree)	Tests whether the tree expressed by the passed type tree is a valid type, and emits an error if that is not the case (e.g.
Void	visitBinary(BinaryTree tree, Void p)	Checks comparison operators, == and !=, for INTERNING violations.
Void	visitMethod(MethodTree tree, Void p)	Checks that the method or constructor obeys override and subtype rules to all overridden methods.
Void	visitMethodInvocation(MethodInvocationTree tree, Void p)	If lint option "dotequals" is specified, warn if the .equals method is used where reference equality is safe.

Methods inherited from class org.checkerframework.common.basetype.BaseTypeVisitor

checkAccess, checkAccessAllowed, checkArguments, checkArrayInitialization, checkConditionalPostcondition, checkConstructorInvocation, checkContract, checkDefaultConstructor, checkExceptionParameter, checkExplicitAnnotationsOnIntersectionBounds, checkExtendsAndImplements, checkExtendsOrImplements, checkFieldInvariantDeclarations, checkForPolymorphicQualifiers, checkForPolymorphicQualifiers, checkMethodInvocability, checkMethodReferenceAsOverride, checkOverride, checkOverride, checkPostcondition, checkPreconditions, checkPurity, checkQualifierParameter, checkSuperConstructorCall, checkThisConstructorCall, checkThisOrSuperConstructorCall, checkThrownExpression, checkTypeArguments, checkTypecastRedundancy, checkTypecastSafety, checkVarargs, commonAssignmentCheck, commonAssignmentCheck, commonAssignmentCheck, commonAssignmentCheckEndDiagnostic, commonAssignmentCheckEndDiagnostic, commonAssignmentCheckStartDiagnostic, createOverrideChecker, createTypeFactory, createTypeFactoryPublic, createTypeValidator, enclosingMemberSelect, enclosingStatement, getExceptionParameterLowerBoundAnnotations, getThrowUpperBoundAnnotations, getTypeFactory, isValidUse, isValidUse, isValidUse, reportMethodInvocabilityError, reportPurityErrors, scan, setRoot, shouldSkipUses, shouldWarnAboutIrrelevantJavaTypes, skipReceiverSubtypeCheck, testAnnotationInsertion, testJointJavacJavaParserVisitor, testTypevarContainment, typeCheckVectorCopyIntoArgument, validateType, visitAnnotatedType, visitAnnotatedType, visitAnnotation, visitAssignment, visitCatch, visitClass, visitCompilationUnit, visitCompoundAssignment, visitConditionalExpression, visitEnhancedForLoop, visitIdentifier, visitInstanceOf, visitLambdaExpression, visitMemberReference, visitNewArray, visitNewClass, visitReturn, visitSwitchExpression17, visitThrow, visitTypeCast, visitTypeParameter, visitUnary, visitVariable, warnAboutIrrelevantJavaTypes, warnRedundantAnnotations

Methods inherited from class org.checkerframework.framework.source.SourceVisitor

visit

Methods inherited from class com.sun.source.util.TreePathScanner

getCurrentPath, scan

Methods inherited from class com.sun.source.util.TreeScanner

reduce, scan, visitArrayAccess, visitArrayType, visitAssert, visitBindingPattern, visitBlock, visitBreak, visitCase, visitContinue, visitDefaultCaseLabel, visitDoWhileLoop, visitEmptyStatement, visitErroneous, visitExports, visitExpressionStatement, visitForLoop, visitGuardedPattern, visitIf, visitImport, visitIntersectionType, visitLabeledStatement, visitLiteral, visitMemberSelect, visitModifiers, visitModule, visitOpens, visitOther, visitPackage, visitParameterizedType, visitParenthesized, visitParenthesizedPattern, visitPrimitiveType, visitProvides, visitRequires, visitSwitch, visitSwitchExpression, visitSynchronized, visitTry, visitUnionType, visitUses, visitWhileLoop, visitWildcard, visitYield

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

InterningVisitor

public InterningVisitor(BaseTypeChecker checker)

Create an InterningVisitor.

Method Details

visitBinary

public Void visitBinary(BinaryTree tree,
 Void p)

Checks comparison operators, == and !=, for INTERNING violations.

Specified by:

visitBinary in interface TreeVisitor<Void,Void>

Overrides:

visitBinary in class TreeScanner<Void,Void>

visitMethodInvocation

public Void visitMethodInvocation(MethodInvocationTree tree,
 Void p)

If lint option "dotequals" is specified, warn if the .equals method is used where reference equality is safe.

Specified by:

visitMethodInvocation in interface TreeVisitor<Void,Void>

Overrides:

visitMethodInvocation in class BaseTypeVisitor<InterningAnnotatedTypeFactory>

visitMethod

public Void visitMethod(MethodTree tree,
 Void p)

Description copied from class: BaseTypeVisitor

Checks that the method or constructor obeys override and subtype rules to all overridden methods. (Uses the pseudo-assignment logic to do so.)

The override rule specifies that a method, m1, may override a method m2 only if:

• m1 return type is a subtype of m2
• m1 receiver type is a supertype of m2
• m1 parameters are supertypes of corresponding m2 parameters

Also, it issues a "missing.this" error for static method annotated receivers.

Specified by:

visitMethod in interface TreeVisitor<Void,Void>

Overrides:

visitMethod in class BaseTypeVisitor<InterningAnnotatedTypeFactory>

processClassTree

public void processClassTree(ClassTree classTree)

Method to implement the @UsesObjectEquals functionality. If a class is annotated with @UsesObjectEquals, it must:

• not override .equals(Object) and be a subclass of a class annotated with @UsesObjectEquals, or
• override equals(Object) with body "this == arg"

If a class is not annotated with @UsesObjectEquals, it must:

• not have a superclass annotated with @UsesObjectEquals

Overrides:

processClassTree in class BaseTypeVisitor<InterningAnnotatedTypeFactory>

Parameters:

classTree - class to check

See Also:

• SourceVisitor.visitClass(com.sun.source.tree.ClassTree, java.lang.Object)

checkConstructorResult

protected void checkConstructorResult(AnnotatedTypeMirror.AnnotatedExecutableType constructorType,
 ExecutableElement constructorElement)

Description copied from class: BaseTypeVisitor

Issue a warning if the result type of the constructor declaration is not top. If it is a supertype of the class, then a conflicting.annos error will also be issued by BaseTypeVisitor.isValidUse(AnnotatedTypeMirror.AnnotatedDeclaredType,AnnotatedTypeMirror.AnnotatedDeclaredType,Tree).

Overrides:

checkConstructorResult in class BaseTypeVisitor<InterningAnnotatedTypeFactory>

Parameters:

constructorType - the AnnotatedExecutableType for the constructor

constructorElement - the element that declares the constructor

validateTypeOf

public boolean validateTypeOf(Tree tree)

Description copied from class: BaseTypeVisitor

Tests whether the tree expressed by the passed type tree is a valid type, and emits an error if that is not the case (e.g. '@Mutable String'). If the tree is a method or constructor, check the return type.

Overrides:

validateTypeOf in class BaseTypeVisitor<InterningAnnotatedTypeFactory>

Parameters:

tree - the AST type supplied by the user

Returns:

true if the tree is a valid type

isInvocationOfEquals

public static boolean isInvocationOfEquals(MethodInvocationTree tree)

Tests whether a method invocation is an invocation of Object.equals(java.lang.Object) with one argument.

Returns true even if a method overloads Object.equals(Object), because of the common idiom of writing an equals method with a non-Object parameter, in addition to the equals method that overrides Object.equals(Object).

Parameters:

tree - a method invocation tree

Returns:

true iff tree is a invocation of equals()

isTypeCastSafe

protected boolean isTypeCastSafe(AnnotatedTypeMirror castType,
 AnnotatedTypeMirror exprType)

Description copied from class: BaseTypeVisitor

Returns true if the cast is safe.

Only primary qualifiers are checked unless the command line option "checkCastElementType" is supplied.

Overrides:

isTypeCastSafe in class BaseTypeVisitor<InterningAnnotatedTypeFactory>

Parameters:

castType - annotated type of the cast

exprType - annotated type of the casted expression

Returns:

true if the type cast is safe, false otherwise