Fix array destructuring

Array destructuring should use iterator objects, not integer
indexes.

Change-Id: I769bb1d63246da6bc45233f7a6e9a8e5ddc53a4d
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

3 files changed, 28 insertions, 9 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 97b71ddbcc..ffb318168c 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -476,27 +476,44 @@ void Codegen::destructureElementList(const Codegen::Reference &array, PatternEle
 {
     RegisterScope scope(this);
 
-    int index = 0;
+    Reference iterator = Reference::fromStackSlot(this);
+
+    array.loadInAccumulator();
+    Instruction::GetIterator iteratorObjInstr;
+    iteratorObjInstr.iterator = 1; // ForEachType::Of
+    bytecodeGenerator->addInstruction(iteratorObjInstr);
+    iterator.storeConsumeAccumulator();
+
+    BytecodeGenerator::Label end = bytecodeGenerator->newLabel();
+
     for (PatternElementList *p = bindingList; p; p = p->next) {
-        for (Elision *elision = p->elision; elision; elision = elision->next)
-            ++index;
+        for (Elision *elision = p->elision; elision; elision = elision->next) {
+            iterator.loadInAccumulator();
+            Instruction::IteratorNext next;
+            next.returnUndefinedWhenDone = true;
+            bytecodeGenerator->addInstruction(next);
+        }
 
         RegisterScope scope(this);
 
-        Reference idx = Reference::fromConst(this, Encode(index));
-        Reference property = Reference::fromSubscript(array, idx);
+        iterator.loadInAccumulator();
+        Instruction::IteratorNext next;
+        next.returnUndefinedWhenDone = true;
+        bytecodeGenerator->addInstruction(next);
         PatternElement *e = p->element;
         if (!e)
             continue;
         if (e->type != PatternElement::RestElement) {
-            initializeAndDestructureBindingElement(e, property);
-            if (hasError)
+            initializeAndDestructureBindingElement(e, Reference::fromAccumulator(this));
+            if (hasError) {
+                end.link();
                 return;
+            }
         } else {
             throwSyntaxError(bindingList->firstSourceLocation(), QString::fromLatin1("Support for rest elements in binding arrays not implemented!"));
         }
-        ++index;
     }
+    end.link();
 }
 
 void Codegen::destructurePattern(Pattern *p, const Reference &rhs)
@@ -2666,6 +2683,7 @@ bool Codegen::visit(ForEachStatement *ast)
     in.link();
     iterator.loadInAccumulator();
     Instruction::IteratorNext next;
+    next.returnUndefinedWhenDone = false;
     bytecodeGenerator->addInstruction(next);
     Instruction::JumpEmpty jump;
     BytecodeGenerator::Jump done = bytecodeGenerator->addJumpInstruction(jump);
diff --git a/src/qml/compiler/qv4instr_moth.cpp b/src/qml/compiler/qv4instr_moth.cpp
index 58aa7d7cfd..7446848fb5 100644
--- a/src/qml/compiler/qv4instr_moth.cpp
+++ b/src/qml/compiler/qv4instr_moth.cpp
@@ -434,6 +434,7 @@ void dumpBytecode(const char *code, int len, int nLocals, int nFormals, int /*st
         MOTH_END_INSTR(GetIterator)
 
         MOTH_BEGIN_INSTR(IteratorNext)
+            d << returnUndefinedWhenDone;
         MOTH_END_INSTR(IteratorNext)
 
         MOTH_BEGIN_INSTR(DeleteMember)
diff --git a/src/qml/compiler/qv4instr_moth_p.h b/src/qml/compiler/qv4instr_moth_p.h
index 301a43a519..de01b808e9 100644
--- a/src/qml/compiler/qv4instr_moth_p.h
+++ b/src/qml/compiler/qv4instr_moth_p.h
@@ -122,7 +122,7 @@ QT_BEGIN_NAMESPACE
 #define INSTR_PopScriptContext(op) INSTRUCTION(op, PopScriptContext, 0)
 #define INSTR_PopContext(op) INSTRUCTION(op, PopContext, 1, reg)
 #define INSTR_GetIterator(op) INSTRUCTION(op, GetIterator, 1, iterator)
-#define INSTR_IteratorNext(op) INSTRUCTION(op, IteratorNext, 0)
+#define INSTR_IteratorNext(op) INSTRUCTION(op, IteratorNext, 1, returnUndefinedWhenDone)
 #define INSTR_DeleteMember(op) INSTRUCTION(op, DeleteMember, 2, member, base)
 #define INSTR_DeleteSubscript(op) INSTRUCTION(op, DeleteSubscript, 2, base, index)
 #define INSTR_DeleteName(op) INSTRUCTION(op, DeleteName, 1, name)