Package com.google.javascript.jscomp

Class TypeCheck

java.lang.Object

com.google.javascript.jscomp.TypeCheck

All Implemented Interfaces:

CompilerPass, NodeTraversal.Callback

public final class TypeCheck
extends java.lang.Object
implements NodeTraversal.Callback, CompilerPass

Checks the types of JS expressions against any declared type information.

Field Summary

Fields

Modifier and Type	Field	Description
static DiagnosticType	INEXISTENT_PROPERTY
static DiagnosticType	STRICT_INEXISTENT_PROPERTY
static DiagnosticType	STRICT_INEXISTENT_UNION_PROPERTY

Constructor Summary

Constructors

Constructor	Description
TypeCheck(AbstractCompiler compiler, ReverseAbstractInterpreter reverseInterpreter, JSTypeRegistry typeRegistry)
TypeCheck(AbstractCompiler compiler, ReverseAbstractInterpreter reverseInterpreter, JSTypeRegistry typeRegistry, @Nullable TypedScope topScope, @Nullable com.google.javascript.jscomp.TypedScopeCreator scopeCreator)

Method Summary

Modifier and Type	Method	Description
void	process(Node externsRoot, Node jsRoot)	Main entry point for this phase of processing.
TypedScope	processForTesting(Node externsRoot, Node jsRoot)	Main entry point of this phase for testing code.
boolean	shouldTraverse(NodeTraversal t, Node n, Node parent)	Visits a node in preorder (before its children) and decides whether the node and its children should be traversed.
void	visit(NodeTraversal t, Node n, Node parent)	This is the meat of the type checking.

Methods inherited from class java.lang.Object

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

Field Detail

INEXISTENT_PROPERTY

public static final DiagnosticType INEXISTENT_PROPERTY

STRICT_INEXISTENT_PROPERTY

public static final DiagnosticType STRICT_INEXISTENT_PROPERTY

STRICT_INEXISTENT_UNION_PROPERTY

public static final DiagnosticType STRICT_INEXISTENT_UNION_PROPERTY

Constructor Detail

TypeCheck

public TypeCheck(AbstractCompiler compiler,
                 ReverseAbstractInterpreter reverseInterpreter,
                 JSTypeRegistry typeRegistry,
                 @Nullable TypedScope topScope,
                 @Nullable com.google.javascript.jscomp.TypedScopeCreator scopeCreator)

TypeCheck

public TypeCheck(AbstractCompiler compiler,
                 ReverseAbstractInterpreter reverseInterpreter,
                 JSTypeRegistry typeRegistry)

Method Detail

process

public void process(Node externsRoot,
                    Node jsRoot)

Main entry point for this phase of processing. This follows the pattern for JSCompiler phases.

Specified by:

process in interface CompilerPass

Parameters:

externsRoot - The root of the externs parse tree.

jsRoot - The root of the input parse tree to be checked.

processForTesting

public TypedScope processForTesting(Node externsRoot,
                                    Node jsRoot)

Main entry point of this phase for testing code.

Parameters:

externsRoot - may be null or a ROOT node. If null the externs are not typechecked. Note: the externs node must always exist in the AST, even if not typechecked.

jsRoot - must be a ROOT node and the second child of the global ROOT.

shouldTraverse

public boolean shouldTraverse(NodeTraversal t,
                              Node n,
                              Node parent)

Description copied from interface: NodeTraversal.Callback

Visits a node in preorder (before its children) and decides whether the node and its children should be traversed.

If this method returns true, the node will be visited by NodeTraversal.Callback.visit(NodeTraversal, Node, Node) in postorder and its children will be visited by both NodeTraversal.Callback.shouldTraverse(NodeTraversal, Node, Node) in preorder and by NodeTraversal.Callback.visit(NodeTraversal, Node, Node) in postorder.

If this method returns false, the node will not be visited by NodeTraversal.Callback.visit(NodeTraversal, Node, Node) and its children will neither be visited by NodeTraversal.Callback.shouldTraverse(NodeTraversal, Node, Node) nor NodeTraversal.Callback.visit(NodeTraversal, Node, Node).

Siblings are always visited left-to-right.

Implementations can have side-effects (e.g. modify the parse tree). Removing the current node is legal, but removing or reordering nodes above the current node may cause nodes to be visited twice or not at all.

Specified by:

shouldTraverse in interface NodeTraversal.Callback

Parameters:

t - The current traversal.

n - The current node.

parent - The parent of the current node.

Returns:

whether the children of this node should be visited

visit

public void visit(NodeTraversal t,
                  Node n,
                  Node parent)

This is the meat of the type checking. It is basically one big switch, with each case representing one type of parse tree node. The individual cases are usually pretty straightforward.

Specified by:

visit in interface NodeTraversal.Callback

Parameters:

t - The node traversal object that supplies context, such as the scope chain to use in name lookups as well as error reporting.

n - The node being visited.

parent - The parent of the node n.