PreParser scope analysis: simplify DeclareAndInitializeVariables.

Now we have declarations too, so it doesn't matter whether preparser
produces the same unresolved variables as the parser.

BUG=v8:5501, v8:5516
R=verwaest@chromium.org

Review-Url: https://codereview.chromium.org/2623583004
Cr-Commit-Position: refs/heads/master@{#42174}

src/parsing/preparser.cc

@@ -297,26 +297,12 @@ void PreParser::DeclareAndInitializeVariables(
     ZoneList<const AstRawString*>* names, bool* ok) {
   if (declaration->pattern.variables_ != nullptr) {
     DCHECK(FLAG_lazy_inner_functions);
-    /* Mimic what Parser does when declaring variables (see
-       Parser::PatternRewriter::VisitVariableProxy).
-
-       var + no initializer -> RemoveUnresolved
-       let / const + no initializer -> RemoveUnresolved
-       var + initializer -> RemoveUnresolved followed by NewUnresolved
-       let / const + initializer -> RemoveUnresolved
-    */
     Scope* scope = declaration_descriptor->hoist_scope;
     if (scope == nullptr) {
       scope = this->scope();
     }
-    if (declaration->initializer.IsEmpty() ||
-        (declaration_descriptor->mode == VariableMode::LET ||
-         declaration_descriptor->mode == VariableMode::CONST)) {
     for (auto variable : *(declaration->pattern.variables_)) {
       declaration_descriptor->scope->RemoveUnresolved(variable);
-      }
-    }
-    for (auto variable : *(declaration->pattern.variables_)) {
       scope->DeclareVariableName(variable->raw_name(),
                                  declaration_descriptor->mode);
     }

test/cctest/test-parsing.cc

@@ -8692,12 +8692,17 @@ TEST(NoPessimisticContextAllocation) {
       {"function inner() { for (let {y, x: my_var} of []) { } my_var; }", true},
       {"function inner() { for (let {a, my_var} in {}) { } my_var; }", true},
       {"function inner() { for (let {a, my_var} of []) { } my_var; }", true},
+      {"function inner() { for (let my_var = 0; my_var < 1; ++my_var) { } "
+       "my_var }",
+       true},
       // No pessimistic context allocation:
       {"function inner() { var my_var; my_var; }", false},
       {"function inner() { var my_var; }", false},
+      {"function inner() { var my_var = 0; }", false},
       {"function inner() { if (true) { var my_var; } my_var; }", false},
       {"function inner() { let my_var; my_var; }", false},
       {"function inner() { let my_var; }", false},
+      {"function inner() { let my_var = 0; }", false},
       {"function inner() { const my_var = 0; my_var; }", false},
       {"function inner() { const my_var = 0; }", false},
       {"function inner() { var [a, my_var] = [1, 2]; my_var; }", false},
@@ -8871,6 +8876,9 @@ TEST(NoPessimisticContextAllocation) {
       {"function inner() { for (var my_var = 0; my_var < 1; ++my_var) { my_var "
        "} }",
        false},
+      {"function inner() { for (var my_var = 0; my_var < 1; ++my_var) { } "
+       "my_var }",
+       false},
       {"function inner() { for (let a = 0, my_var = 0; my_var < 1; ++my_var) { "
        "my_var } }",
        false},