[es6] Check declaration conflicts between non-simple parameters and the function body

Also, more tests for parameters containing functions or eval or both.

R=adamk@chromium.org, caitpotter88@gmail.com, littledan@chromium.org
BUG=v8:811
LOG=N

Review URL: https://codereview.chromium.org/1225413005

Cr-Commit-Position: refs/heads/master@{#29752}

src/parser.cc

@@ -4443,6 +4443,9 @@ ZoneList<Statement*>* Parser::ParseEagerFunctionBody(
 
     inner_scope->set_end_position(scanner()->location().end_pos);
     inner_scope = inner_scope->FinalizeBlockScope();
+    if (inner_scope != nullptr) {
+      CheckConflictingVarDeclarations(inner_scope, CHECK_OK);
+    }
 
     result->Add(init_block, zone());
     result->Add(inner_block, zone());

src/scopes.cc

@@ -575,12 +575,21 @@ Declaration* Scope::CheckConflictingVarDeclarations() {
   int length = decls_.length();
   for (int i = 0; i < length; i++) {
     Declaration* decl = decls_[i];
-    if (decl->mode() != VAR) continue;
+    if (decl->mode() != VAR && !is_block_scope()) continue;
     const AstRawString* name = decl->proxy()->raw_name();
 
     // Iterate through all scopes until and including the declaration scope.
+    // If the declaration scope is a (declaration) block scope, also continue
+    // (that is to handle the special inner scope of functions with
+    // destructuring parameters, which may not shadow any variables from
+    // the surrounding function scope).
     Scope* previous = NULL;
     Scope* current = decl->scope();
+    // Lexical vs lexical conflicts within the same scope have already been
+    // captured in Parser::Declare. The only conflicts we still need to check
+    // are lexical vs VAR, or any declarations within a declaration block scope
+    // vs lexical declarations in its surrounding (function) scope.
+    if (decl->mode() != VAR) current = current->outer_scope_;
     do {
       // There is a conflict if there exists a non-VAR binding.
       Variable* other_var = current->variables_.Lookup(name);
@@ -589,7 +598,7 @@ Declaration* Scope::CheckConflictingVarDeclarations() {
       }
       previous = current;
       current = current->outer_scope_;
-    } while (!previous->is_declaration_scope());
+    } while (!previous->is_declaration_scope() || previous->is_block_scope());
   }
   return NULL;
 }

test/mjsunit/harmony/destructuring.js

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 //
 // Flags: --harmony-destructuring --harmony-computed-property-names
-// Flags: --harmony-arrow-functions
+// Flags: --harmony-arrow-functions --harmony-rest-parameters
 
 (function TestObjectLiteralPattern() {
   var { x : x, y : y } = { x : 1, y : 2 };
@@ -226,6 +226,12 @@
     assertEquals(43, y);
   }
 
+  {
+    let {x, y = () => eval("x+1")} = {x:42};
+    assertEquals(42, x);
+    assertEquals(43, y());
+  }
+
   {
     let {x = function() {return y+1;}, y} = {y:42};
     assertEquals(43, x());
@@ -729,6 +735,25 @@
   assertEquals(1, f4({}));
   function f5({a = x}) { 'use strict'; function x() {}; return a; }
   assertEquals(1, f5({}));
+  // TODO(rossberg): Apparently, eval in default expressions is not working yet.
+  // function f6({a = eval("x")}) { var x; return a; }
+  // assertEquals(1, f6({}));
+  // function f61({a = eval("x")}) { 'use strict'; var x; return a; }
+  // assertEquals(1, f61({}));
+  // function f62({a = eval("'use strict'; x")}) { var x; return a; }
+  // assertEquals(1, f62({}));
+  function f7({a = function() { return x }}) { var x; return a(); }
+  assertEquals(1, f7({}));
+  function f8({a = () => x}) { var x; return a(); }
+  assertEquals(1, f8({}));
+  // function f9({a = () => eval("x")}) { var x; return a(); }
+  // assertEquals(1, f9({}));
+  // function f91({a = () => eval("x")}) { 'use strict'; var x; return a(); }
+  // assertEquals(1, f91({}));
+  // function f92({a = () => { 'use strict'; return eval("x") }}) { var x; return a(); }
+  // assertEquals(1, f92({}));
+  // function f93({a = () => eval("'use strict'; x")}) { var x; return a(); }
+  // assertEquals(1, f93({}));
 
   var g1 = ({a = x}) => { var x = 2; return a; };
   assertEquals(1, g1({}));
@@ -740,25 +765,82 @@
   assertEquals(1, g4({}));
   var g5 = ({a = x}) => { 'use strict'; function x() {}; return a; };
   assertEquals(1, g5({}));
-
-  var f6 = function f({x = f}) { var f; return x; }
-  assertSame(f6, f6({}));
-  var f7 = function f({x = f}) { function f() {}; return x; }
-  assertSame(f7, f7({}));
-  var f8 = function f({x = f}) { 'use strict'; let f; return x; }
-  assertSame(f8, f8({}));
-  var f9 = function f({x = f}) { 'use strict'; const f = 0; return x; }
-  assertSame(f9, f9({}));
-  var f10 = function f({x = f}) { 'use strict'; function f() {}; return x; }
-  assertSame(f10, f10({}));
-  var f11 = function f({f = 7, x = f}) { return x; }
-  assertSame(7, f11({}));
+  // var g6 = ({a = eval("x")}) => { var x; return a; };
+  // assertEquals(1, g6({}));
+  // var g61 = ({a = eval("x")}) => { 'use strict'; var x; return a; };
+  // assertEquals(1, g61({}));
+  // var g62 = ({a = eval("'use strict'; x")}) => { var x; return a; };
+  // assertEquals(1, g62({}));
+  var g7 = ({a = function() { return x }}) => { var x; return a(); };
+  assertEquals(1, g7({}));
+  var g8 = ({a = () => x}) => { var x; return a(); };
+  assertEquals(1, g8({}));
+  // var g9 = ({a = () => eval("x")}) => { var x; return a(); };
+  // assertEquals(1, g9({}));
+  // var g91 = ({a = () => eval("x")}) => { 'use strict'; var x; return a(); };
+  // assertEquals(1, g91({}));
+  // var g92 = ({a = () => { 'use strict'; return eval("x") }}) => { var x; return a(); };
+  // assertEquals(1, g92({}));
+  // var g93 = ({a = () => eval("'use strict'; x")}) => { var x; return a(); };
+  // assertEquals(1, g93({}));
+
+  var f11 = function f({x = f}) { var f; return x; }
+  assertSame(f11, f11({}));
+  var f12 = function f({x = f}) { function f() {}; return x; }
+  assertSame(f12, f12({}));
+  var f13 = function f({x = f}) { 'use strict'; let f; return x; }
+  assertSame(f13, f13({}));
+  var f14 = function f({x = f}) { 'use strict'; const f = 0; return x; }
+  assertSame(f14, f14({}));
+  var f15 = function f({x = f}) { 'use strict'; function f() {}; return x; }
+  assertSame(f15, f15({}));
+  var f16 = function f({f = 7, x = f}) { return x; }
+  assertSame(7, f16({}));
 
   var y = 'a';
   function f20({[y]: x}) { var y = 'b'; return x; }
   assertEquals(1, f20({a: 1, b: 2}));
+  // function f21({[eval('y')]: x}) { var y = 'b'; return x; }
+  // assertEquals(1, f21({a: 1, b: 2}));
   var g20 = ({[y]: x}) => { var y = 'b'; return x; };
   assertEquals(1, g20({a: 1, b: 2}));
+  // var g21 = ({[eval('y')]: x}) => { var y = 'b'; return x; };
+  // assertEquals(1, g21({a: 1, b: 2}));
+
+  // TODO(caitp): TDZ for rest parameters is not working yet.
+  // function f30({x = a}, ...a) {}
+  // assertThrows(() => f30({}), ReferenceError);
+  // function f31({x = eval("a")}, ...a) {}
+  // assertThrows(() => f31({}), ReferenceError);
+  // function f32({x = eval("a")}, ...a) { 'use strict'; }
+  // assertThrows(() => f32({}), ReferenceError);
+  // function f33({x = eval("'use strict'; a")}, ...a) {}
+  // assertThrows(() => f33({}), ReferenceError);
+  function f34({x = function() { return a }}, ...a) { return x()[0] }
+  assertEquals(4, f34({}, 4));
+  function f35({x = () => a}, ...a) { return x()[0] }
+  assertEquals(4, f35({}, 4));
+  // function f36({x = () => eval("a")}, ...a) { return x()[0] }
+  // assertEquals(4, f36({}, 4));
+  // function f37({x = () => eval("a")}, ...a) { 'use strict'; return x()[0] }
+  // assertEquals(4, f37({}, 4));
+  // function f38({x = () => { 'use strict'; return eval("a") }}, ...a) { return x()[0] }
+  // assertEquals(4, f38({}, 4));
+  // function f39({x = () => eval("'use strict'; a")}, ...a) { return x()[0] }
+  // assertEquals(4, f39({}, 4));
+
+  // var g30 = ({x = a}, ...a) => {};
+  // assertThrows(() => g30({}), ReferenceError);
+  // var g31 = ({x = eval("a")}, ...a) => {};
+  // assertThrows(() => g31({}), ReferenceError);
+  // var g32 = ({x = eval("a")}, ...a) => { 'use strict'; };
+  // assertThrows(() => g32({}), ReferenceError);
+  // var g33 = ({x = eval("'use strict'; a")}, ...a) => {};
+  // assertThrows(() => g33({}), ReferenceError);
+  var g34 = ({x = function() { return a }}, ...a) => { return x()[0] };
+  assertEquals(4, g34({}, 4));
+  var g35 = ({x = () => a}, ...a) => { return x()[0] };
+  assertEquals(4, g35({}, 4));
 })();
 
 
@@ -770,10 +852,15 @@
   assertThrows("'use strict';var f = ({x,x}) => {};", SyntaxError);
   assertThrows("'use strict';var f = (x, {x}) => {};", SyntaxError);
 
-  function ok(x) { var x; }; ok();
-  // TODO(rossberg): Check for variable collision.
-  // assertThrows("function f({x}) { var x; }; f({});", SyntaxError);
-  // assertThrows("'use strict'; function f({x}) { let x = 0; }; f({});", SyntaxError);
+  function ok1(x) { var x; return x; };
+  assertEquals(1, ok1(1));
+  function ok2(x) { 'use strict'; { let x = 2; return x; } };
+  assertEquals(2, ok2(1));
+
+  assertThrows("function f({x}) { var x; }; f({});", SyntaxError);
+  assertThrows("function f({x}) { { var x; } }; f({});", SyntaxError);
+  assertThrows("'use strict'; function f(x) { let x = 0; }; f({});", SyntaxError);
+  assertThrows("'use strict'; function f({x}) { let x = 0; }; f({});", SyntaxError);
 }());