Step 27.c.i filters arguments binding out of body-level var,
and function_var_names_count calculated before FunctionScopeData::new call doesn't reflect it.
FunctionScopeData::new doesn't require var_count to be exact value,
because it's used only for capacity.
the parameter name should be max_var_count, and needs some comment.
Step 27.c.i filters
argumentsbinding out of body-level var, andfunction_var_names_countcalculated beforeFunctionScopeData::newcall doesn't reflect it.FunctionScopeData::newdoesn't requirevar_countto be exact value, because it's used only for capacity.the parameter name should be
max_var_count, and needs some comment.