RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-23 18:45:07 +00:00
Code Issues Activity Actions

LibJS: Limit scope of 'for' loop variables

Browse source 
This required 2 changes:
1. In the parser, create a new variable scope, so the variable is
   declared in it instead of the scope in which the 'for' is found.
2. On execute, push the variable into the newly created block. Existing
   code created an empty block (no variables, no arguments) which
   allows Interpreter::enter_scope() to skip the creation of a new
   environment, therefore when the variable initializer is executed, it
   sets the variable to the outer scope. By attaching the variable to
   the new block, the block gets a new environment.

This is only needed for 'let' / 'const' declarations, since 'var'
declarations are expected to leak.

Fixes: #2103
This commit is contained in:
Yonatan Goldschmidt 2020-05-05 01:58:53 +03:00 • committed by Andreas Kling
parent ab652fa1ee
commit b184f12aaf
3 changed files with 35 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

3
Libraries/LibJS/AST.cpp
View file

@ -251,6 +251,9 @@ Value ForStatement::execute(Interpreter& interpreter) const
if (m_init && m_init->is_variable_declaration() && static_cast<const VariableDeclaration*>(m_init.ptr())->declaration_kind() != DeclarationKind::Var) {
wrapper = create_ast_node<BlockStatement>();
NonnullRefPtrVector<VariableDeclaration> decls;
decls.append(*static_cast<const VariableDeclaration*>(m_init.ptr()));
wrapper->add_variables(decls);
interpreter.enter_scope(*wrapper, {}, ScopeType::Block);
}