org.checkerframework.framework.util.typeinference

Class TypeArgInferenceUtil

java.lang.Object

org.checkerframework.framework.util.typeinference.TypeArgInferenceUtil

public class TypeArgInferenceUtil
extends Object

Miscellaneous utilities to help in type argument inference.

Constructor Summary

Constructors

Constructor and Description
TypeArgInferenceUtil()

Method Summary

Modifier and Type	Method and Description
static AnnotatedTypeMirror	assignedTo(AnnotatedTypeFactory atypeFactory, TreePath path) Returns the annotated type that the leaf of path is assigned to, if it is within an assignment context.
static AnnotatedTypeMirror	assignedToVariable(AnnotatedTypeFactory atypeFactory, Tree assignmentContext) If the variable's type is a type variable, return getAnnotatedTypeLhsNoTypeVarDefault(tree).
static void	checkForUninferredTypes(AnnotatedTypeMirror type) Throws an exception if the type is an uninferred type argument.
static boolean	containsTypeParameter(AnnotatedTypeMirror type, Collection<TypeVariable> typeVariables) Returns true if type contains a use of a type variable in typeVariables.
static AnnotationMirrorMap<AnnotationMirror>	createHierarchyMap(AnnotationMirrorSet annos, QualifierHierarchy qualifierHierarchy) Take a set of annotations and separate them into a mapping of (hierarchy top &rArr; annotations in hierarchy).
static List<AnnotatedTypeMirror>	getArgumentTypes(ExpressionTree methodInvocation, AnnotatedTypeFactory typeFactory) Returns a list of boxed annotated types corresponding to the arguments in methodInvocation.
static boolean	isATarget(AnnotatedTypeMirror type, Set<TypeVariable> targetTypeVars) Given a set of type variables for which we are inferring a type, returns true if type is a use of a type variable in the list of targetTypeVars.
static AnnotatedTypeMirror	leastUpperBound(AnnotatedTypeFactory typeFactory, Iterable<AnnotatedTypeMirror> types) Successively calls least upper bound on the elements of types.
static Set<TypeVariable>	methodTypeToTargets(AnnotatedTypeMirror.AnnotatedExecutableType methodType) Given an AnnotatedExecutableType return a set of type variables that represents the generic type parameters of that method.
static AnnotatedTypeMirror	substitute(Map<TypeVariable,AnnotatedTypeMirror> substitutions, AnnotatedTypeMirror toModify) Create a copy of toModify.
static AnnotatedTypeMirror	substitute(TypeVariable typeVariable, AnnotatedTypeMirror substitution, AnnotatedTypeMirror toModify) Replace all uses of typeVariable with substitution in a copy of toModify using the normal substitution rules.

Methods inherited from class java.lang.Object

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

Constructor Detail

TypeArgInferenceUtil

public TypeArgInferenceUtil()

Method Detail

getArgumentTypes

public static List<AnnotatedTypeMirror> getArgumentTypes(ExpressionTree methodInvocation,
                                                         AnnotatedTypeFactory typeFactory)

Returns a list of boxed annotated types corresponding to the arguments in methodInvocation.

Parameters:

methodInvocation - MethodInvocationTree or NewClassTree

typeFactory - type factory

Returns:

a list of boxed annotated types corresponding to the arguments in methodInvocation.

isATarget

public static boolean isATarget(AnnotatedTypeMirror type,
                                Set<TypeVariable> targetTypeVars)

Given a set of type variables for which we are inferring a type, returns true if type is a use of a type variable in the list of targetTypeVars.

methodTypeToTargets

public static Set<TypeVariable> methodTypeToTargets(AnnotatedTypeMirror.AnnotatedExecutableType methodType)

Given an AnnotatedExecutableType return a set of type variables that represents the generic type parameters of that method.

assignedTo

public static AnnotatedTypeMirror assignedTo(AnnotatedTypeFactory atypeFactory,
                                             TreePath path)

Returns the annotated type that the leaf of path is assigned to, if it is within an assignment context. Returns the annotated type that the method invocation at the leaf is assigned to. If the result is a primitive, return the boxed version.

Returns:

type that path leaf is assigned to

assignedToVariable

public static AnnotatedTypeMirror assignedToVariable(AnnotatedTypeFactory atypeFactory,
                                                     Tree assignmentContext)

If the variable's type is a type variable, return getAnnotatedTypeLhsNoTypeVarDefault(tree). Rational:

For example:

 <S> S bar () {...}

 <T> T foo(T p) {
     T local = bar();
     return local;
   }
 

During type argument inference of bar, the assignment context is local. If the local variable default is used, then the type of assignment context type is @Nullable T and the type argument inferred for bar() is @Nullable T. And an incompatible types in return error is issued.

If instead, the local variable default is not applied, then the assignment context type is T (with lower bound @NonNull Void and upper bound @Nullable Object) and the type argument inferred for bar() is T. During dataflow, the type of local is refined to T and the return is legal.

If the assignment context type was a declared type, for example:

 <S> S bar () {...}
 Object foo() {
     Object local = bar();
     return local;
 }
 

The local variable default must be used or else the assignment context type is missing an annotation. So, an incompatible types in return error is issued in the above code. We could improve type argument inference in this case and by using the lower bound of S instead of the local variable default.

Parameters:

atypeFactory - AnnotatedTypeFactory

assignmentContext - VariableTree

Returns:

AnnotatedTypeMirror of Assignment context

containsTypeParameter

public static boolean containsTypeParameter(AnnotatedTypeMirror type,
                                            Collection<TypeVariable> typeVariables)

Returns true if type contains a use of a type variable in typeVariables.

Parameters:

type - type to search

typeVariables - collection of type varibles

Returns:

true if type contains a use of a type variable in typeVariables

createHierarchyMap

public static AnnotationMirrorMap<AnnotationMirror> createHierarchyMap(AnnotationMirrorSet annos,
                                                                       QualifierHierarchy qualifierHierarchy)

Take a set of annotations and separate them into a mapping of (hierarchy top ⇒ annotations in hierarchy).

checkForUninferredTypes

public static void checkForUninferredTypes(AnnotatedTypeMirror type)

Throws an exception if the type is an uninferred type argument.

The error will be caught in DefaultTypeArgumentInference#infer and inference will be aborted, but type-checking will continue.

substitute

public static AnnotatedTypeMirror substitute(TypeVariable typeVariable,
                                             AnnotatedTypeMirror substitution,
                                             AnnotatedTypeMirror toModify)

Replace all uses of typeVariable with substitution in a copy of toModify using the normal substitution rules. Return the copy

See Also:

TypeVariableSubstitutor

substitute

public static AnnotatedTypeMirror substitute(Map<TypeVariable,AnnotatedTypeMirror> substitutions,
                                             AnnotatedTypeMirror toModify)

Create a copy of toModify. In the copy, for each pair typeVariable ⇒ annotated type replace uses of typeVariable with the corresponding annotated type using normal substitution rules (@see TypeVariableSubstitutor). Return the copy.

leastUpperBound

public static AnnotatedTypeMirror leastUpperBound(AnnotatedTypeFactory typeFactory,
                                                  Iterable<AnnotatedTypeMirror> types)

Successively calls least upper bound on the elements of types. Unlike leastUpperBound, this method will box primitives if necessary