Support destructuring inside catch()

Change-Id: Ib60b56ac6a7111446e01235564a4cf92ad8ad025
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

8 files changed, 42 insertions, 18 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index f55e6205dc..8c6964930d 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -2954,12 +2954,6 @@ bool Codegen::visit(ThrowStatement *ast)
 void Codegen::handleTryCatch(TryStatement *ast)
 {
     Q_ASSERT(ast);
-    if (_context->isStrict &&
-        (ast->catchExpression->name == QLatin1String("eval") || ast->catchExpression->name == QLatin1String("arguments"))) {
-        throwSyntaxError(ast->catchExpression->identifierToken, QStringLiteral("Catch variable name may not be eval or arguments in strict mode"));
-        return;
-    }
-
     RegisterScope scope(this);
     BytecodeGenerator::Label noException = bytecodeGenerator->newLabel();
     {
diff --git a/src/qml/compiler/qv4compilercontext.cpp b/src/qml/compiler/qv4compilercontext.cpp
index 67afea28ab..07e19811a8 100644
--- a/src/qml/compiler/qv4compilercontext.cpp
+++ b/src/qml/compiler/qv4compilercontext.cpp
@@ -81,7 +81,7 @@ bool Context::addLocalVar(const QString &name, Context::MemberType type, Variabl
         if (formals && formals->containsName(name))
             return (scope == VariableScope::Var);
     }
-    if (!isCatchBlock || name != catchedVariable) {
+    if (!isCatchBlock || name != caughtVariable) {
         MemberMap::iterator it = members.find(name);
         if (it != members.end()) {
             if (scope != VariableScope::Var || (*it).scope != VariableScope::Var)
@@ -178,7 +178,7 @@ int Context::emitBlockHeader(Codegen *codegen)
                 Instruction::PushCatchContext catchContext;
                 catchContext.index = blockIndex;
                 catchContext.reg = contextReg = bytecodeGenerator->newRegister();
-                catchContext.name = codegen->registerString(catchedVariable);
+                catchContext.name = codegen->registerString(caughtVariable);
                 bytecodeGenerator->addInstruction(catchContext);
             } else {
                 Instruction::PushBlockContext blockContext;
diff --git a/src/qml/compiler/qv4compilercontext_p.h b/src/qml/compiler/qv4compilercontext_p.h
index 20bee6583a..6838610d1c 100644
--- a/src/qml/compiler/qv4compilercontext_p.h
+++ b/src/qml/compiler/qv4compilercontext_p.h
@@ -155,7 +155,7 @@ struct Context {
     bool requiresExecutionContext = false;
     bool isWithBlock = false;
     bool isCatchBlock = false;
-    QString catchedVariable;
+    QString caughtVariable;
 
     enum UsesArgumentsObject {
         ArgumentsObjectUnknown,
diff --git a/src/qml/compiler/qv4compilercontrolflow_p.h b/src/qml/compiler/qv4compilercontrolflow_p.h
index b89226c411..db83af0022 100644
--- a/src/qml/compiler/qv4compilercontrolflow_p.h
+++ b/src/qml/compiler/qv4compilercontrolflow_p.h
@@ -422,6 +422,10 @@ struct ControlFlowCatch : public ControlFlowUnwind
         Reference::storeConstOnStack(cg, QV4::Encode::undefined(), controlFlowTemp);
         generator()->setExceptionHandler(&catchUnwindLabel);
 
+        if (catchExpression->patternElement->bindingIdentifier.isEmpty())
+            // destructuring pattern
+            cg->initializeAndDestructureBindingElement(catchExpression->patternElement, Reference::fromName(cg, QStringLiteral("@caught")));
+        // skip the additional block
         cg->statementList(catchExpression->statement->statements);
 
         insideCatch = false;
diff --git a/src/qml/compiler/qv4compilerscanfunctions.cpp b/src/qml/compiler/qv4compilerscanfunctions.cpp
index f7100a1d1a..4dbd11ef1c 100644
--- a/src/qml/compiler/qv4compilerscanfunctions.cpp
+++ b/src/qml/compiler/qv4compilerscanfunctions.cpp
@@ -387,8 +387,19 @@ bool ScanFunctions::visit(Catch *ast)
     enterEnvironment(ast, ContextType::Block);
     _context->name = QLatin1String("CatchBlock");
     _context->isCatchBlock = true;
-    _context->catchedVariable = ast->name.toString();
-    _context->addLocalVar(ast->name.toString(), Context::MemberType::VariableDefinition, VariableScope::Let);
+    QString caughtVar = ast->patternElement->bindingIdentifier;
+    if (caughtVar.isEmpty())
+        caughtVar = QStringLiteral("@caught");
+    _context->addLocalVar(caughtVar, Context::MemberType::VariableDefinition, VariableScope::Let);
+
+    _context->caughtVariable = caughtVar;
+    if (_context->isStrict &&
+        (caughtVar == QLatin1String("eval") || caughtVar == QLatin1String("arguments"))) {
+        _cg->throwSyntaxError(ast->identifierToken, QStringLiteral("Catch variable name may not be eval or arguments in strict mode"));
+        return false;
+    }
+    Node::accept(ast->patternElement, this);
+    // skip the block statement
     Node::accept(ast->statement->statements, this);
     return false;
 }
@@ -567,7 +578,7 @@ void ScanFunctions::calcEscapingVariables()
         }
         if (c->contextType == ContextType::Block && c->isCatchBlock) {
             c->requiresExecutionContext = true;
-            auto m = c->members.find(c->catchedVariable);
+            auto m = c->members.find(c->caughtVariable);
             m->canEscape = true;
         }
         if (allVarsEscape) {
diff --git a/src/qml/parser/qqmljs.g b/src/qml/parser/qqmljs.g
index 8e71b8a42b..f162d123f5 100644
--- a/src/qml/parser/qqmljs.g
+++ b/src/qml/parser/qqmljs.g
@@ -3396,7 +3396,7 @@ TryStatement: T_TRY Block Catch Finally;
 Catch: T_CATCH T_LPAREN CatchParameter T_RPAREN Block;
 /.
     case $rule_number: {
-        AST::Catch *node = new (pool) AST::Catch(stringRef(3), sym(5).Block);
+        AST::Catch *node = new (pool) AST::Catch(sym(3).PatternElement, sym(5).Block);
         node->catchToken = loc(1);
         node->lparenToken = loc(2);
         node->identifierToken = loc(3);
@@ -3415,9 +3415,23 @@ Finally: T_FINALLY Block;
 ./
 
 CatchParameter: BindingIdentifier;
+/.
+    case $rule_number: {
+        AST::PatternElement *node = new (pool) AST::PatternElement(stringRef(1));
+        node->identifierToken = loc(1);
+        node->scope = AST::VariableScope::Let;
+        sym(1).Node = node;
+    } break;
+./
 
 CatchParameter: BindingPattern;
-/.  case $rule_number: { UNIMPLEMENTED; } ./
+/.
+    case $rule_number: {
+        AST::PatternElement *node = new (pool) AST::PatternElement(sym(1).Pattern);
+        node->scope = AST::VariableScope::Let;
+        sym(1).Node = node;
+    } break;
+./
 
 DebuggerStatement: T_DEBUGGER T_AUTOMATIC_SEMICOLON; -- automatic semicolon
 DebuggerStatement: T_DEBUGGER T_SEMICOLON;
diff --git a/src/qml/parser/qqmljsast.cpp b/src/qml/parser/qqmljsast.cpp
index 6c0e394a34..cc8b290bc9 100644
--- a/src/qml/parser/qqmljsast.cpp
+++ b/src/qml/parser/qqmljsast.cpp
@@ -938,6 +938,7 @@ void TryStatement::accept0(Visitor *visitor)
 void Catch::accept0(Visitor *visitor)
 {
     if (visitor->visit(this)) {
+        accept(patternElement, visitor);
         accept(statement, visitor);
     }
 
diff --git a/src/qml/parser/qqmljsast_p.h b/src/qml/parser/qqmljsast_p.h
index e54d1aea31..36060f7358 100644
--- a/src/qml/parser/qqmljsast_p.h
+++ b/src/qml/parser/qqmljsast_p.h
@@ -2063,9 +2063,9 @@ class QML_PARSER_EXPORT Catch: public Node
 public:
     QQMLJS_DECLARE_AST_NODE(Catch)
 
-    Catch(const QStringRef &n, Block *stmt):
-        name (n), statement (stmt)
-        { kind = K; }
+    Catch(PatternElement *p, Block *stmt)
+        : patternElement(p), statement(stmt)
+    { kind = K; }
 
     void accept0(Visitor *visitor) override;
 
@@ -2076,7 +2076,7 @@ public:
     { return statement->lastSourceLocation(); }
 
 // attributes
-    QStringRef name;
+    PatternElement *patternElement;
     Block *statement;
     SourceLocation catchToken;
     SourceLocation lparenToken;