Package org.checkerframework.checker.mustcall

Class MustCallVisitor

java.lang.Object

com.sun.source.util.TreeScanner<Void,Void>

com.sun.source.util.TreePathScanner<Void,Void>

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

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

org.checkerframework.checker.mustcall.MustCallVisitor

All Implemented Interfaces:

TreeVisitor<Void,Void>

public class MustCallVisitor
extends BaseTypeVisitor<MustCallAnnotatedTypeFactory>

The visitor for the Must Call Checker. This visitor is similar to BaseTypeVisitor, but overrides methods that don't work well with the MustCall type hierarchy because it doesn't use the top type as the default type.

Nested Class Summary

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

BaseTypeVisitor.FoundRequired, BaseTypeVisitor.OverrideChecker

Field Summary

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

assumePureGetters, atypeFactory, checker, DETERMINISTIC, ignoreTargetLocations, IMPURE, methodTree, positions, PURE, qualAllowedLocations, 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
MustCallVisitor(BaseTypeChecker checker)	Creates a new MustCallVisitor.

Method Summary

Modifier and Type	Method	Description
protected void	checkConstructorResult(AnnotatedTypeMirror.AnnotatedExecutableType constructorType, ExecutableElement constructorElement)	This method typically issues a warning if the result type of the constructor is not top, because in top-default type systems that indicates a potential problem.
protected AnnotationMirrorSet	getExceptionParameterLowerBoundAnnotations()	Change the default for exception parameter lower bounds to bottom (the default), to prevent false positives.
boolean	isValidUse(AnnotatedTypeMirror.AnnotatedDeclaredType declarationType, AnnotatedTypeMirror.AnnotatedDeclaredType useType, Tree tree)	Tests that the qualifiers present on useType are valid qualifiers, given the qualifiers on the declaration of the type, declarationType.
protected boolean	skipReceiverSubtypeCheck(MethodInvocationTree tree, AnnotatedTypeMirror methodDefinitionReceiver, AnnotatedTypeMirror methodCallReceiver)	Indicates whether to skip subtype checks on the receiver when checking method invocability.
protected boolean	validateType(Tree tree, AnnotatedTypeMirror type)	Tests whether the type and corresponding type tree is a valid type, and emits an error if that is not the case (e.g.
Void	visitAnnotation(AnnotationTree tree, Void p)	Does not issue any warnings.
Void	visitAssignment(AssignmentTree tree, Void p)	Performs two checks: subtyping and assignability checks, using BaseTypeVisitor.commonAssignmentCheck(Tree, ExpressionTree, String, Object[]).
Void	visitReturn(ReturnTree tree, Void p)	Checks that the type of the return expression is a subtype of the enclosing method required return type.

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

checkAccess, checkAccessAllowed, checkArguments, checkArrayInitialization, checkConditionalPostcondition, checkConstructorInvocation, checkContract, checkDefaultConstructor, checkEnclosingExpr, 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, contractExpressionAndType, createOverrideChecker, createQualAllowedLocations, createTypeFactory, createTypeFactoryPublic, createTypeValidator, enclosingMemberSelect, enclosingStatement, getThrowUpperBoundAnnotations, getTypeFactory, isTypeCastSafe, isValidUse, isValidUse, processClassTree, reportCommonAssignmentError, reportMethodInvocabilityError, reportPurityErrors, scan, setRoot, shouldSkipUses, shouldWarnAboutIrrelevantJavaTypes, testAnnotationInsertion, testJointJavacJavaParserVisitor, testTypevarContainment, typeCheckVectorCopyIntoArgument, validateTargetLocation, validateTypeOf, validateVariablesTargetLocation, visitAnnotatedType, visitAnnotatedType, visitCatch, visitClass, visitCompilationUnit, visitCompoundAssignment, visitConditionalExpression, visitEnhancedForLoop, visitIdentifier, visitInstanceOf, visitLambdaExpression, visitMemberReference, visitMethod, visitMethodInvocation, visitNewArray, visitNewClass, 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, visitAnyPattern, visitArrayAccess, visitArrayType, visitAssert, visitBinary, visitBindingPattern, visitBlock, visitBreak, visitCase, visitConstantCaseLabel, visitContinue, visitDeconstructionPattern, visitDefaultCaseLabel, visitDoWhileLoop, visitEmptyStatement, visitErroneous, visitExports, visitExpressionStatement, visitForLoop, visitIf, visitImport, visitIntersectionType, visitLabeledStatement, visitLiteral, visitMemberSelect, visitModifiers, visitModule, visitOpens, visitOther, visitPackage, visitParameterizedType, visitParenthesized, visitPatternCaseLabel, visitPrimitiveType, visitProvides, visitRequires, visitStringTemplate, 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

MustCallVisitor

public MustCallVisitor(BaseTypeChecker checker)

Creates a new MustCallVisitor.

Parameters:

checker - the type-checker associated with this visitor

Method Details

visitReturn

public Void visitReturn(ReturnTree tree,
 Void p)

Description copied from class: BaseTypeVisitor

Checks that the type of the return expression is a subtype of the enclosing method required return type. If not, it issues a "return.type.incompatible" error.

Specified by:

visitReturn in interface TreeVisitor<Void,Void>

Overrides:

visitReturn in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>

visitAssignment

public Void visitAssignment(AssignmentTree tree,
 Void p)

Description copied from class: BaseTypeVisitor

Performs two checks: subtyping and assignability checks, using BaseTypeVisitor.commonAssignmentCheck(Tree, ExpressionTree, String, Object[]).

If the subtype check fails, it issues an "assignment.type.incompatible" error.

Specified by:

visitAssignment in interface TreeVisitor<Void,Void>

Overrides:

visitAssignment in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>

validateType

protected boolean validateType(Tree tree,
 AnnotatedTypeMirror type)

Description copied from class: BaseTypeVisitor

Tests whether the type and corresponding 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, tests the return type.

Overrides:

validateType in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>

Parameters:

tree - the type tree supplied by the user

type - the type corresponding to tree

Returns:

true if the type is valid

isValidUse

public boolean isValidUse(AnnotatedTypeMirror.AnnotatedDeclaredType declarationType,
 AnnotatedTypeMirror.AnnotatedDeclaredType useType,
 Tree tree)

Description copied from class: BaseTypeVisitor

Tests that the qualifiers present on useType are valid qualifiers, given the qualifiers on the declaration of the type, declarationType.

The check is shallow, as it does not descend into generic or array types (i.e. only performing the validity check on the raw type or outermost array dimension). BaseTypeVisitor.validateTypeOf(Tree) would call this for each type argument or array dimension separately.

In most cases, useType simply needs to be a subtype of declarationType. If a type system makes exceptions to this rule, its implementation should override this method.

This method is not called if BaseTypeValidator.shouldCheckTopLevelDeclaredOrPrimitiveType(AnnotatedTypeMirror, Tree) returns false -- by default, it is not called on the top level for locals and expressions. To enforce a type validity property everywhere, override methods such as BaseTypeValidator.visitDeclared(org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedDeclaredType, com.sun.source.tree.Tree) rather than this method.

Overrides:

isValidUse in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>

Parameters:

declarationType - the type of the class (TypeElement)

useType - the use of the class (instance type)

tree - the tree where the type is used

Returns:

true if the useType is a valid use of elemType

skipReceiverSubtypeCheck

protected boolean skipReceiverSubtypeCheck(MethodInvocationTree tree,
 AnnotatedTypeMirror methodDefinitionReceiver,
 AnnotatedTypeMirror methodCallReceiver)

Description copied from class: BaseTypeVisitor

Indicates whether to skip subtype checks on the receiver when checking method invocability. A visitor may, for example, allow a method to be invoked even if the receivers are siblings in a hierarchy, provided that some other condition (implemented by the visitor) is satisfied.

Overrides:

skipReceiverSubtypeCheck in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>

Parameters:

tree - the method invocation tree

methodDefinitionReceiver - the ATM of the receiver of the method definition

methodCallReceiver - the ATM of the receiver of the method call

Returns:

whether to skip subtype checks on the receiver

checkConstructorResult

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

This method typically issues a warning if the result type of the constructor is not top, because in top-default type systems that indicates a potential problem. The Must Call Checker does not need this warning, because it expects the type of all constructors to be MustCall({}) (by default) or some other MustCall type, not the top type.

Instead, this method checks that the result type of a constructor is a supertype of the declared type on the class, if one exists.

Overrides:

checkConstructorResult in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>

Parameters:

constructorType - an AnnotatedExecutableType for the constructor

constructorElement - element that declares the constructor

getExceptionParameterLowerBoundAnnotations

protected AnnotationMirrorSet getExceptionParameterLowerBoundAnnotations()

Change the default for exception parameter lower bounds to bottom (the default), to prevent false positives. This is unsound; see the discussion on https://github.com/typetools/checker-framework/issues/3839.

TODO: change checking of throws clauses to require that the thrown exception is @MustCall({}). This would probably eliminate most of the same false positives, without adding undue false positives.

Overrides:

getExceptionParameterLowerBoundAnnotations in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>

Returns:

a set containing only the @MustCall({}) annotation

visitAnnotation

public Void visitAnnotation(AnnotationTree tree,
 Void p)

Does not issue any warnings.

This implementation prevents recursing into annotation arguments. Annotation arguments are literals, which don't have must-call obligations.

Annotation arguments are treated as return locations for the purposes of defaulting, rather than parameter locations. This causes them to default incorrectly when the annotation is defined in bytecode. See https://github.com/typetools/checker-framework/issues/3178 for an explanation of why this is necessary to avoid false positives.

Specified by:

visitAnnotation in interface TreeVisitor<Void,Void>

Overrides:

visitAnnotation in class BaseTypeVisitor<MustCallAnnotatedTypeFactory>