Don't skip hole checks inside patterns in parameter lists

src/parsing/parser.cc

Index: src/parsing/parser.cc
diff --git a/src/parsing/parser.cc b/src/parsing/parser.cc
index 2cf97bc14b539ee965d16b76ec7a9e2d80205d9b..0ae1fb619a70ff1aa8bf224fa5a613ec99ebcea4 100644
--- a/src/parsing/parser.cc
+++ b/src/parsing/parser.cc
@@ -2939,9 +2939,6 @@ Block* Parser::BuildParameterInitializationBlock(
     // TODO(adamk): Should this be kNoSourcePosition, since
     // it's just copying from a temp var to the real param var?
     descriptor.initialization_pos = parameter.pattern->position();
-    // The initializer position which will end up in,
-    // Variable::initializer_position(), used for hole check elimination.
-    int initializer_position = parameter.pattern->position();
     Expression* initial_value =
         factory()->NewVariableProxy(parameters.scope->parameter(i));
     if (parameter.initializer != nullptr) {
@@ -2957,7 +2954,6 @@ Block* Parser::BuildParameterInitializationBlock(
       initial_value = factory()->NewConditional(
           condition, parameter.initializer, initial_value, kNoSourcePosition);
       descriptor.initialization_pos = parameter.initializer->position();
-      initializer_position = parameter.initializer_end_position;
     }
 
     Scope* param_scope = scope();
@@ -2980,7 +2976,7 @@ Block* Parser::BuildParameterInitializationBlock(
 
     BlockState block_state(&scope_state_, param_scope);
     DeclarationParsingResult::Declaration decl(
-        parameter.pattern, initializer_position, initial_value);
+        parameter.pattern, parameter.initializer_end_position, initial_value);
     PatternRewriter::DeclareAndInitializeVariables(
         this, param_block, &descriptor, &decl, nullptr, CHECK_OK);