[parser] Skipping inner funcs: fix destructuring catch variables.

Make PreParser match what Parser does.

BUG=v8:5516

Change-Id: I2801206fd17b9a5047bc43c6112f4945971596b7
Reviewed-on: https://chromium-review.googlesource.com/544949
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Daniel Vogelheim <vogelheim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46169}

src/parsing/preparser.h

@@ -1060,11 +1060,16 @@ class PreParser : public ParserBase<PreParser> {
 
   V8_INLINE void RewriteCatchPattern(CatchInfo* catch_info, bool* ok) {
     if (track_unresolved_variables_) {
-      if (catch_info->name.string_ != nullptr) {
-        // Unlike in the parser, we need to declare the catch variable as LET
-        // variable, so that it won't get hoisted out of the scope.
-        catch_info->scope->DeclareVariableName(catch_info->name.string_, LET);
+      const AstRawString* catch_name = catch_info->name.string_;
+      if (catch_name == nullptr) {
+        catch_name = ast_value_factory()->dot_catch_string();
       }
+      // Unlike in the parser, we need to declare the catch variable as LET
+      // variable, so that it won't get hoisted out of the scope. (Parser uses
+      // DeclareLocal instead of DeclareVariable to prevent hoisting.) Another
+      // solution would've been to add DeclareLocalName just for this purpose.
+      catch_info->scope->DeclareVariableName(catch_name, LET);
+
       if (catch_info->pattern.variables_ != nullptr) {
         for (auto variable : *catch_info->pattern.variables_) {
           scope()->DeclareVariableName(variable->raw_name(), LET);

test/cctest/parsing/test-preparser.cc

@@ -593,7 +593,11 @@ TEST(PreParserScopeAnalysis) {
       {"try { } catch(var1) { var1 = 3; }"},
       {"try { } catch(var1) { function f() { var1; } }"},
       {"try { } catch(var1) { function f() { var1 = 3; } }"},
-      // FIXME(marja): Add tests for destructuring catch.
+
+      {"try { } catch({var1, var2}) { function f() { var1 = 3; } }"},
+      {"try { } catch([var1, var2]) { function f() { var1 = 3; } }"},
+      {"try { } catch({}) { }"},
+      {"try { } catch([]) { }"},
 
       // Shadowing the catch variable
       {"try { } catch(var1) { var var1 = 3; }"},