Merge pull request #3538 from ethereum/emitEvents

emit pseudo-keyword for events.

25 files changed, 327 insertions, 27 deletions

diff --git a/Changelog.md b/Changelog.md
index f0d00416..3af3a99d 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -4,6 +4,7 @@ Features:
  * Code Generator: Assert that ``k != 0`` for ``molmod(a, b, k)`` and ``addmod(a, b, k)`` as experimental 0.5.0 feature.
  * Standard JSON: Reject badly formatted invalid JSON inputs.
  * Type Checker: Disallow uninitialized storage pointers as experimental 0.5.0 feature.
+ * Support and recommend using ``emit EventName();`` to call events explicitly.
  * Syntax Analyser: Do not warn about experimental features if they do not concern code generation.
 
 Bugfixes:
diff --git a/docs/contracts.rst b/docs/contracts.rst
index 368b7819..ee203263 100644
--- a/docs/contracts.rst
+++ b/docs/contracts.rst
@@ -724,10 +724,12 @@ All non-indexed arguments will be stored in the data part of the log.
         );
 
         function deposit(bytes32 _id) public payable {
-            // Any call to this function (even deeply nested) can
-            // be detected from the JavaScript API by filtering
-            // for `Deposit` to be called.
-            Deposit(msg.sender, _id, msg.value);
+            // Events are emitted using `emit`, followed by
+            // the name of the event and the arguments
+            // (if any) in parentheses. Any such invocation
+            // (even deeply nested) can be detected from
+            // the JavaScript API by filtering for `Deposit`.
+            emit Deposit(msg.sender, _id, msg.value);
         }
     }
 
diff --git a/docs/grammar.txt b/docs/grammar.txt
index e700c946..a5c2acf3 100644
--- a/docs/grammar.txt
+++ b/docs/grammar.txt
@@ -63,7 +63,7 @@ StateMutability = 'pure' | 'constant' | 'view' | 'payable'
 Block = '{' Statement* '}'
 Statement = IfStatement | WhileStatement | ForStatement | Block | InlineAssemblyStatement |
             ( DoWhileStatement | PlaceholderStatement | Continue | Break | Return |
-              Throw | SimpleStatement ) ';'
+              Throw | EmitStatement | SimpleStatement ) ';'
 
 ExpressionStatement = Expression
 IfStatement = 'if' '(' Expression ')' Statement ( 'else' Statement )?
@@ -77,6 +77,7 @@ Continue = 'continue'
 Break = 'break'
 Return = 'return' Expression?
 Throw = 'throw'
+EmitStatement = 'emit' FunctionCall
 VariableDefinition = ('var' IdentifierList | VariableDeclaration) ( '=' Expression )?
 IdentifierList = '(' ( Identifier? ',' )* Identifier? ')'
 
diff --git a/docs/introduction-to-smart-contracts.rst b/docs/introduction-to-smart-contracts.rst
index c297a8ad..11e07292 100644
--- a/docs/introduction-to-smart-contracts.rst
+++ b/docs/introduction-to-smart-contracts.rst
@@ -80,7 +80,7 @@ registering with username and password - all you need is an Ethereum keypair.
 
 ::
 
-    pragma solidity ^0.4.0;
+    pragma solidity ^0.4.20; // should actually be 0.4.21
 
     contract Coin {
         // The keyword "public" makes those variables
@@ -107,7 +107,7 @@ registering with username and password - all you need is an Ethereum keypair.
             if (balances[msg.sender] < amount) return;
             balances[msg.sender] -= amount;
             balances[receiver] += amount;
-            Sent(msg.sender, receiver, amount);
+            emit Sent(msg.sender, receiver, amount);
         }
     }
 
@@ -157,10 +157,10 @@ single account.
 .. index:: event
 
 The line ``event Sent(address from, address to, uint amount);`` declares
-a so-called "event" which is fired in the last line of the function
+a so-called "event" which is emitted in the last line of the function
 ``send``. User interfaces (as well as server applications of course) can
-listen for those events being fired on the blockchain without much
-cost. As soon as it is fired, the listener will also receive the
+listen for those events being emitted on the blockchain without much
+cost. As soon as it is emitted, the listener will also receive the
 arguments ``from``, ``to`` and ``amount``, which makes it easy to track
 transactions. In order to listen for this event, you would use ::
 
diff --git a/docs/solidity-by-example.rst b/docs/solidity-by-example.rst
index b8e158ac..e5b44c98 100644
--- a/docs/solidity-by-example.rst
+++ b/docs/solidity-by-example.rst
@@ -214,7 +214,7 @@ activate themselves.
 
 ::
 
-    pragma solidity ^0.4.11;
+    pragma solidity ^0.4.20; // should actually be 0.4.21
 
     contract SimpleAuction {
         // Parameters of the auction. Times are either
@@ -282,7 +282,7 @@ activate themselves.
             }
             highestBidder = msg.sender;
             highestBid = msg.value;
-            HighestBidIncreased(msg.sender, msg.value);
+            emit HighestBidIncreased(msg.sender, msg.value);
         }
 
         /// Withdraw a bid that was overbid.
@@ -325,7 +325,7 @@ activate themselves.
 
             // 2. Effects
             ended = true;
-            AuctionEnded(highestBidder, highestBid);
+            emit AuctionEnded(highestBidder, highestBid);
 
             // 3. Interaction
             beneficiary.transfer(highestBid);
@@ -371,7 +371,7 @@ high or low invalid bids.
 
 ::
 
-    pragma solidity ^0.4.11;
+    pragma solidity ^0.4.20; // should actually be 0.4.21
 
     contract BlindAuction {
         struct Bid {
@@ -509,7 +509,7 @@ high or low invalid bids.
             onlyAfter(revealEnd)
         {
             require(!ended);
-            AuctionEnded(highestBidder, highestBid);
+            emit AuctionEnded(highestBidder, highestBid);
             ended = true;
             beneficiary.transfer(highestBid);
         }
@@ -524,7 +524,7 @@ Safe Remote Purchase
 
 ::
 
-    pragma solidity ^0.4.11;
+    pragma solidity ^0.4.20; // should actually be 0.4.21
 
     contract Purchase {
         uint public value;
@@ -574,7 +574,7 @@ Safe Remote Purchase
             onlySeller
             inState(State.Created)
         {
-            Aborted();
+            emit Aborted();
             state = State.Inactive;
             seller.transfer(this.balance);
         }
@@ -589,7 +589,7 @@ Safe Remote Purchase
             condition(msg.value == (2 * value))
             payable
         {
-            PurchaseConfirmed();
+            emit PurchaseConfirmed();
             buyer = msg.sender;
             state = State.Locked;
         }
@@ -601,7 +601,7 @@ Safe Remote Purchase
             onlyBuyer
             inState(State.Locked)
         {
-            ItemReceived();
+            emit ItemReceived();
             // It is important to change the state first because
             // otherwise, the contracts called using `send` below
             // can call in again here.
diff --git a/docs/structure-of-a-contract.rst b/docs/structure-of-a-contract.rst
index a9a7ed52..4a0873df 100644
--- a/docs/structure-of-a-contract.rst
+++ b/docs/structure-of-a-contract.rst
@@ -86,14 +86,14 @@ Events are convenience interfaces with the EVM logging facilities.
 
 ::
 
-    pragma solidity ^0.4.0;
+    pragma solidity ^0.4.20; // should actually be 0.4.21
 
     contract SimpleAuction {
         event HighestBidIncreased(address bidder, uint amount); // Event
 
         function bid() public payable {
             // ...
-            HighestBidIncreased(msg.sender, msg.value); // Triggering event
+            emit HighestBidIncreased(msg.sender, msg.value); // Triggering event
         }
     }
 
diff --git a/docs/types.rst b/docs/types.rst
index 55eaa69a..3611bc3e 100644
--- a/docs/types.rst
+++ b/docs/types.rst
@@ -470,7 +470,7 @@ Example that shows how to use internal function types::
 
 Another example that uses external function types::
 
-    pragma solidity ^0.4.11;
+    pragma solidity ^0.4.20; // should actually be 0.4.21
 
     contract Oracle {
       struct Request {
@@ -481,7 +481,7 @@ Another example that uses external function types::
       event NewRequest(uint);
       function query(bytes data, function(bytes memory) external callback) public {
         requests.push(Request(data, callback));
-        NewRequest(requests.length - 1);
+        emit NewRequest(requests.length - 1);
       }
       function reply(uint requestID, bytes response) public {
         // Here goes the check that the reply comes from a trusted source
diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index 0ee16c89..2914472a 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -955,6 +955,16 @@ void TypeChecker::endVisit(Return const& _return)
 	}
 }
 
+void TypeChecker::endVisit(EmitStatement const& _emit)
+{
+	if (
+		_emit.eventCall().annotation().kind != FunctionCallKind::FunctionCall ||
+		dynamic_cast<FunctionType const&>(*type(_emit.eventCall().expression())).kind() != FunctionType::Kind::Event
+	)
+		m_errorReporter.typeError(_emit.eventCall().expression().location(), "Expression has to be an event invocation.");
+	m_insideEmitStatement = false;
+}
+
 bool TypeChecker::visit(VariableDeclarationStatement const& _statement)
 {
 	if (!_statement.initialValue())
@@ -1531,6 +1541,13 @@ bool TypeChecker::visit(FunctionCall const& _functionCall)
 		else if (functionName->name() == "suicide" && functionType->kind() == FunctionType::Kind::Selfdestruct)
 			m_errorReporter.warning(_functionCall.location(), "\"suicide\" has been deprecated in favour of \"selfdestruct\"");
 	}
+	if (!m_insideEmitStatement && functionType->kind() == FunctionType::Kind::Event)
+	{
+		if (m_scope->sourceUnit().annotation().experimentalFeatures.count(ExperimentalFeature::V050))
+			m_errorReporter.typeError(_functionCall.location(), "Event invocations have to be prefixed by \"emit\".");
+		else
+			m_errorReporter.warning(_functionCall.location(), "Invoking events without \"emit\" prefix is deprecated.");
+	}
 
 	TypePointers parameterTypes = functionType->parameterTypes();
 
diff --git a/libsolidity/analysis/TypeChecker.h b/libsolidity/analysis/TypeChecker.h
index 344b019d..16796b63 100644
--- a/libsolidity/analysis/TypeChecker.h
+++ b/libsolidity/analysis/TypeChecker.h
@@ -94,6 +94,8 @@ private:
 	virtual bool visit(WhileStatement const& _whileStatement) override;
 	virtual bool visit(ForStatement const& _forStatement) override;
 	virtual void endVisit(Return const& _return) override;
+	virtual bool visit(EmitStatement const&) override { m_insideEmitStatement = true; return true; }
+	virtual void endVisit(EmitStatement const& _emit) override;
 	virtual bool visit(VariableDeclarationStatement const& _variable) override;
 	virtual void endVisit(ExpressionStatement const& _statement) override;
 	virtual bool visit(Conditional const& _conditional) override;
@@ -130,6 +132,9 @@ private:
 
 	ContractDefinition const* m_scope = nullptr;
 
+	/// Flag indicating whether we are currently inside an EmitStatement.
+	bool m_insideEmitStatement = false;
+
 	ErrorReporter& m_errorReporter;
 };
 
diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index feffde64..c0d55aec 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -1197,6 +1197,27 @@ public:
 };
 
 /**
+ * The emit statement is used to emit events: emit EventName(arg1, ..., argn)
+ */
+class EmitStatement: public Statement
+{
+public:
+	explicit EmitStatement(
+		SourceLocation const& _location,
+		ASTPointer<ASTString> const& _docString,
+		ASTPointer<FunctionCall> const& _functionCall
+	):
+		Statement(_location, _docString), m_eventCall(_functionCall) {}
+	virtual void accept(ASTVisitor& _visitor) override;
+	virtual void accept(ASTConstVisitor& _visitor) const override;
+
+	FunctionCall const& eventCall() const { return *m_eventCall; }
+
+private:
+	ASTPointer<FunctionCall> m_eventCall;
+};
+
+/**
  * Definition of a variable as a statement inside a function. It requires a type name (which can
  * also be "var") but the actual assignment can be missing.
  * Examples: var a = 2; uint256 a;
diff --git a/libsolidity/ast/ASTForward.h b/libsolidity/ast/ASTForward.h
index 46675e51..992fe4cd 100644
--- a/libsolidity/ast/ASTForward.h
+++ b/libsolidity/ast/ASTForward.h
@@ -69,6 +69,7 @@ class Continue;
 class Break;
 class Return;
 class Throw;
+class EmitStatement;
 class VariableDeclarationStatement;
 class ExpressionStatement;
 class Expression;
diff --git a/libsolidity/ast/ASTJsonConverter.cpp b/libsolidity/ast/ASTJsonConverter.cpp
index cd9f7eca..4fef67c3 100644
--- a/libsolidity/ast/ASTJsonConverter.cpp
+++ b/libsolidity/ast/ASTJsonConverter.cpp
@@ -540,7 +540,15 @@ bool ASTJsonConverter::visit(Return const& _node)
 
 bool ASTJsonConverter::visit(Throw const& _node)
 {
-	setJsonNode(_node, "Throw", {});;
+	setJsonNode(_node, "Throw", {});
+	return false;
+}
+
+bool ASTJsonConverter::visit(EmitStatement const& _node)
+{
+	setJsonNode(_node, "EmitStatement", {
+		make_pair("eventCall", toJson(_node.eventCall()))
+	});
 	return false;
 }
 
diff --git a/libsolidity/ast/ASTJsonConverter.h b/libsolidity/ast/ASTJsonConverter.h
index 9a886220..88b93699 100644
--- a/libsolidity/ast/ASTJsonConverter.h
+++ b/libsolidity/ast/ASTJsonConverter.h
@@ -91,6 +91,7 @@ public:
 	bool visit(Break const& _node) override;
 	bool visit(Return const& _node) override;
 	bool visit(Throw const& _node) override;
+	bool visit(EmitStatement const& _node) override;
 	bool visit(VariableDeclarationStatement const& _node) override;
 	bool visit(ExpressionStatement const& _node) override;
 	bool visit(Conditional const& _node) override;
diff --git a/libsolidity/ast/ASTPrinter.cpp b/libsolidity/ast/ASTPrinter.cpp
index 23c3cbe1..4273f225 100644
--- a/libsolidity/ast/ASTPrinter.cpp
+++ b/libsolidity/ast/ASTPrinter.cpp
@@ -258,6 +258,13 @@ bool ASTPrinter::visit(Throw const& _node)
 	return goDeeper();
 }
 
+bool ASTPrinter::visit(EmitStatement const& _node)
+{
+	writeLine("EmitStatement");
+	printSourcePart(_node);
+	return goDeeper();
+}
+
 bool ASTPrinter::visit(VariableDeclarationStatement const& _node)
 {
 	writeLine("VariableDeclarationStatement");
@@ -517,6 +524,11 @@ void ASTPrinter::endVisit(Throw const&)
 	m_indentation--;
 }
 
+void ASTPrinter::endVisit(EmitStatement const&)
+{
+	m_indentation--;
+}
+
 void ASTPrinter::endVisit(VariableDeclarationStatement const&)
 {
 	m_indentation--;
diff --git a/libsolidity/ast/ASTPrinter.h b/libsolidity/ast/ASTPrinter.h
index 01e4f7fc..de3bf8a2 100644
--- a/libsolidity/ast/ASTPrinter.h
+++ b/libsolidity/ast/ASTPrinter.h
@@ -76,6 +76,7 @@ public:
 	bool visit(Break const& _node) override;
 	bool visit(Return const& _node) override;
 	bool visit(Throw const& _node) override;
+	bool visit(EmitStatement const& _node) override;
 	bool visit(VariableDeclarationStatement const& _node) override;
 	bool visit(ExpressionStatement const& _node) override;
 	bool visit(Conditional const& _node) override;
@@ -120,6 +121,7 @@ public:
 	void endVisit(Break const&) override;
 	void endVisit(Return const&) override;
 	void endVisit(Throw const&) override;
+	void endVisit(EmitStatement const&) override;
 	void endVisit(VariableDeclarationStatement const&) override;
 	void endVisit(ExpressionStatement const&) override;
 	void endVisit(Conditional const&) override;
diff --git a/libsolidity/ast/ASTVisitor.h b/libsolidity/ast/ASTVisitor.h
index b726d592..b1389f0f 100644
--- a/libsolidity/ast/ASTVisitor.h
+++ b/libsolidity/ast/ASTVisitor.h
@@ -73,6 +73,7 @@ public:
 	virtual bool visit(Break& _node) { return visitNode(_node); }
 	virtual bool visit(Return& _node) { return visitNode(_node); }
 	virtual bool visit(Throw& _node) { return visitNode(_node); }
+	virtual bool visit(EmitStatement& _node) { return visitNode(_node); }
 	virtual bool visit(VariableDeclarationStatement& _node) { return visitNode(_node); }
 	virtual bool visit(ExpressionStatement& _node) { return visitNode(_node); }
 	virtual bool visit(Conditional& _node) { return visitNode(_node); }
@@ -118,6 +119,7 @@ public:
 	virtual void endVisit(Break& _node) { endVisitNode(_node); }
 	virtual void endVisit(Return& _node) { endVisitNode(_node); }
 	virtual void endVisit(Throw& _node) { endVisitNode(_node); }
+	virtual void endVisit(EmitStatement& _node) { endVisitNode(_node); }
 	virtual void endVisit(VariableDeclarationStatement& _node) { endVisitNode(_node); }
 	virtual void endVisit(ExpressionStatement& _node) { endVisitNode(_node); }
 	virtual void endVisit(Conditional& _node) { endVisitNode(_node); }
@@ -175,6 +177,7 @@ public:
 	virtual bool visit(Break const& _node) { return visitNode(_node); }
 	virtual bool visit(Return const& _node) { return visitNode(_node); }
 	virtual bool visit(Throw const& _node) { return visitNode(_node); }
+	virtual bool visit(EmitStatement const& _node) { return visitNode(_node); }
 	virtual bool visit(VariableDeclarationStatement const& _node) { return visitNode(_node); }
 	virtual bool visit(ExpressionStatement const& _node) { return visitNode(_node); }
 	virtual bool visit(Conditional const& _node) { return visitNode(_node); }
@@ -220,6 +223,7 @@ public:
 	virtual void endVisit(Break const& _node) { endVisitNode(_node); }
 	virtual void endVisit(Return const& _node) { endVisitNode(_node); }
 	virtual void endVisit(Throw const& _node) { endVisitNode(_node); }
+	virtual void endVisit(EmitStatement const& _node) { endVisitNode(_node); }
 	virtual void endVisit(VariableDeclarationStatement const& _node) { endVisitNode(_node); }
 	virtual void endVisit(ExpressionStatement const& _node) { endVisitNode(_node); }
 	virtual void endVisit(Conditional const& _node) { endVisitNode(_node); }
diff --git a/libsolidity/ast/AST_accept.h b/libsolidity/ast/AST_accept.h
index 904d9ff6..70ee997e 100644
--- a/libsolidity/ast/AST_accept.h
+++ b/libsolidity/ast/AST_accept.h
@@ -541,6 +541,20 @@ void Throw::accept(ASTConstVisitor& _visitor) const
 	_visitor.endVisit(*this);
 }
 
+void EmitStatement::accept(ASTVisitor& _visitor)
+{
+	if (_visitor.visit(*this))
+		m_eventCall->accept(_visitor);
+	_visitor.endVisit(*this);
+}
+
+void EmitStatement::accept(ASTConstVisitor& _visitor) const
+{
+	if (_visitor.visit(*this))
+		m_eventCall->accept(_visitor);
+	_visitor.endVisit(*this);
+}
+
 void ExpressionStatement::accept(ASTVisitor& _visitor)
 {
 	if (_visitor.visit(*this))
diff --git a/libsolidity/codegen/ContractCompiler.cpp b/libsolidity/codegen/ContractCompiler.cpp
index f463db94..ebb718a5 100644
--- a/libsolidity/codegen/ContractCompiler.cpp
+++ b/libsolidity/codegen/ContractCompiler.cpp
@@ -903,6 +903,15 @@ bool ContractCompiler::visit(Throw const& _throw)
 	return false;
 }
 
+bool ContractCompiler::visit(EmitStatement const& _emit)
+{
+	CompilerContext::LocationSetter locationSetter(m_context, _emit);
+	StackHeightChecker checker(m_context);
+	compileExpression(_emit.eventCall());
+	checker.check();
+	return false;
+}
+
 bool ContractCompiler::visit(VariableDeclarationStatement const& _variableDeclarationStatement)
 {
 	StackHeightChecker checker(m_context);
diff --git a/libsolidity/codegen/ContractCompiler.h b/libsolidity/codegen/ContractCompiler.h
index 1fd80d05..d698dc71 100644
--- a/libsolidity/codegen/ContractCompiler.h
+++ b/libsolidity/codegen/ContractCompiler.h
@@ -109,6 +109,7 @@ private:
 	virtual bool visit(Break const& _breakStatement) override;
 	virtual bool visit(Return const& _return) override;
 	virtual bool visit(Throw const& _throw) override;
+	virtual bool visit(EmitStatement const& _emit) override;
 	virtual bool visit(VariableDeclarationStatement const& _variableDeclarationStatement) override;
 	virtual bool visit(ExpressionStatement const& _expressionStatement) override;
 	virtual bool visit(PlaceholderStatement const&) override;
diff --git a/libsolidity/parsing/Parser.cpp b/libsolidity/parsing/Parser.cpp
index e306e21b..8c97f55f 100644
--- a/libsolidity/parsing/Parser.cpp
+++ b/libsolidity/parsing/Parser.cpp
@@ -897,7 +897,9 @@ ASTPointer<Statement> Parser::parseStatement()
 	case Token::Assembly:
 		return parseInlineAssembly(docString);
 	case Token::Identifier:
-		if (m_insideModifier && m_scanner->currentLiteral() == "_")
+		if (m_scanner->currentLiteral() == "emit")
+			statement = parseEmitStatement(docString);
+		else if (m_insideModifier && m_scanner->currentLiteral() == "_")
 		{
 			statement = ASTNodeFactory(*this).createNode<PlaceholderStatement>(docString);
 			m_scanner->next();
@@ -1015,6 +1017,38 @@ ASTPointer<ForStatement> Parser::parseForStatement(ASTPointer<ASTString> const&
 	);
 }
 
+ASTPointer<EmitStatement> Parser::parseEmitStatement(ASTPointer<ASTString> const& _docString)
+{
+	ASTNodeFactory nodeFactory(*this);
+	m_scanner->next();
+	ASTNodeFactory eventCallNodeFactory(*this);
+
+	if (m_scanner->currentToken() != Token::Identifier)
+		fatalParserError("Expected event name or path.");
+
+	vector<ASTPointer<PrimaryExpression>> path;
+	while (true)
+	{
+		path.push_back(parseIdentifier());
+		if (m_scanner->currentToken() != Token::Period)
+			break;
+		m_scanner->next();
+	};
+
+	auto eventName = expressionFromIndexAccessStructure(path, {});
+	expectToken(Token::LParen);
+
+	vector<ASTPointer<Expression>> arguments;
+	vector<ASTPointer<ASTString>> names;
+	std::tie(arguments, names) = parseFunctionCallArguments();
+	eventCallNodeFactory.markEndPosition();
+	nodeFactory.markEndPosition();
+	expectToken(Token::RParen);
+	auto eventCall = eventCallNodeFactory.createNode<FunctionCall>(eventName, arguments, names);
+	auto statement = nodeFactory.createNode<EmitStatement>(_docString, eventCall);
+	return statement;
+}
+
 ASTPointer<Statement> Parser::parseSimpleStatement(ASTPointer<ASTString> const& _docString)
 {
 	RecursionGuard recursionGuard(*this);
diff --git a/libsolidity/parsing/Parser.h b/libsolidity/parsing/Parser.h
index cfdfea7e..3f780af9 100644
--- a/libsolidity/parsing/Parser.h
+++ b/libsolidity/parsing/Parser.h
@@ -104,6 +104,7 @@ private:
 	ASTPointer<WhileStatement> parseWhileStatement(ASTPointer<ASTString> const& _docString);
 	ASTPointer<WhileStatement> parseDoWhileStatement(ASTPointer<ASTString> const& _docString);
 	ASTPointer<ForStatement> parseForStatement(ASTPointer<ASTString> const& _docString);
+	ASTPointer<EmitStatement> parseEmitStatement(ASTPointer<ASTString> const& docString);
 	/// A "simple statement" can be a variable declaration statement or an expression statement.
 	ASTPointer<Statement> parseSimpleStatement(ASTPointer<ASTString> const& _docString);
 	ASTPointer<VariableDeclarationStatement> parseVariableDeclarationStatement(
diff --git a/std/StandardToken.sol b/std/StandardToken.sol
index 2986cb56..1b218d67 100644
--- a/std/StandardToken.sol
+++ b/std/StandardToken.sol
@@ -40,7 +40,7 @@ contract StandardToken is Token {
 		if (balance[_from] >= _value && balance[_to] + _value >= balance[_to]) {
 			balance[_from] -= _value;
 			balance[_to] += _value;
-			Transfer(_from, _to, _value);
+			emit Transfer(_from, _to, _value);
 			return true;
 		} else {
 			return false;
@@ -49,7 +49,7 @@ contract StandardToken is Token {
 
 	function approve(address _spender, uint256 _value) public returns (bool success) {
 		m_allowance[msg.sender][_spender] = _value;
-		Approval(msg.sender, _spender, _value);
+		emit Approval(msg.sender, _spender, _value);
 		return true;
 	}
 
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index d2528a67..3882e4ea 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -2967,6 +2967,29 @@ BOOST_AUTO_TEST_CASE(event)
 	}
 }
 
+BOOST_AUTO_TEST_CASE(event_emit)
+{
+	char const* sourceCode = R"(
+		contract ClientReceipt {
+			event Deposit(address indexed _from, bytes32 indexed _id, uint _value);
+			function deposit(bytes32 _id) payable {
+				emit Deposit(msg.sender, _id, msg.value);
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+	u256 value(18);
+	u256 id(0x1234);
+	callContractFunctionWithValue("deposit(bytes32)", value, id);
+	BOOST_REQUIRE_EQUAL(m_logs.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].address, m_contractAddress);
+	BOOST_CHECK_EQUAL(h256(m_logs[0].data), h256(u256(value)));
+	BOOST_REQUIRE_EQUAL(m_logs[0].topics.size(), 3);
+	BOOST_CHECK_EQUAL(m_logs[0].topics[0], dev::keccak256(string("Deposit(address,bytes32,uint256)")));
+	BOOST_CHECK_EQUAL(m_logs[0].topics[1], h256(m_sender, h256::AlignRight));
+	BOOST_CHECK_EQUAL(m_logs[0].topics[2], h256(id));
+}
+
 BOOST_AUTO_TEST_CASE(event_no_arguments)
 {
 	char const* sourceCode = R"(
@@ -3009,6 +3032,28 @@ BOOST_AUTO_TEST_CASE(event_access_through_base_name)
 	BOOST_CHECK_EQUAL(m_logs[0].topics[0], dev::keccak256(string("x()")));
 }
 
+BOOST_AUTO_TEST_CASE(event_access_through_base_name_emit)
+{
+	char const* sourceCode = R"(
+		contract A {
+			event x();
+		}
+		contract B is A {
+			function f() returns (uint) {
+				emit A.x();
+				return 1;
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+	callContractFunction("f()");
+	BOOST_REQUIRE_EQUAL(m_logs.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].address, m_contractAddress);
+	BOOST_CHECK(m_logs[0].data.empty());
+	BOOST_REQUIRE_EQUAL(m_logs[0].topics.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].topics[0], dev::keccak256(string("x()")));
+}
+
 BOOST_AUTO_TEST_CASE(events_with_same_name)
 {
 	char const* sourceCode = R"(
@@ -3107,6 +3152,58 @@ BOOST_AUTO_TEST_CASE(events_with_same_name_inherited)
 	BOOST_CHECK_EQUAL(m_logs[0].topics[0], dev::keccak256(string("Deposit(address,uint256)")));
 }
 
+BOOST_AUTO_TEST_CASE(events_with_same_name_inherited_emit)
+{
+	char const* sourceCode = R"(
+		contract A {
+			event Deposit();
+		}
+
+		contract B {
+			event Deposit(address _addr);
+		}
+
+		contract ClientReceipt is A, B {
+			event Deposit(address _addr, uint _amount);
+			function deposit() returns (uint) {
+				emit Deposit();
+				return 1;
+			}
+			function deposit(address _addr) returns (uint) {
+				emit Deposit(_addr);
+				return 1;
+			}
+			function deposit(address _addr, uint _amount) returns (uint) {
+				emit Deposit(_addr, _amount);
+				return 1;
+			}
+		}
+	)";
+	u160 const c_loggedAddress = m_contractAddress;
+
+	compileAndRun(sourceCode);
+	ABI_CHECK(callContractFunction("deposit()"), encodeArgs(u256(1)));
+	BOOST_REQUIRE_EQUAL(m_logs.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].address, m_contractAddress);
+	BOOST_CHECK(m_logs[0].data.empty());
+	BOOST_REQUIRE_EQUAL(m_logs[0].topics.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].topics[0], dev::keccak256(string("Deposit()")));
+
+	ABI_CHECK(callContractFunction("deposit(address)", c_loggedAddress), encodeArgs(u256(1)));
+	BOOST_REQUIRE_EQUAL(m_logs.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].address, m_contractAddress);
+	BOOST_CHECK(m_logs[0].data == encodeArgs(c_loggedAddress));
+	BOOST_REQUIRE_EQUAL(m_logs[0].topics.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].topics[0], dev::keccak256(string("Deposit(address)")));
+
+	ABI_CHECK(callContractFunction("deposit(address,uint256)", c_loggedAddress, u256(100)), encodeArgs(u256(1)));
+	BOOST_REQUIRE_EQUAL(m_logs.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].address, m_contractAddress);
+	BOOST_CHECK(m_logs[0].data == encodeArgs(c_loggedAddress, 100));
+	BOOST_REQUIRE_EQUAL(m_logs[0].topics.size(), 1);
+	BOOST_CHECK_EQUAL(m_logs[0].topics[0], dev::keccak256(string("Deposit(address,uint256)")));
+}
+
 BOOST_AUTO_TEST_CASE(event_anonymous)
 {
 	char const* sourceCode = R"(
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index 7c03d7cb..27761066 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -7785,6 +7785,62 @@ BOOST_AUTO_TEST_CASE(no_address_members_on_contract)
 	CHECK_ERROR(text, TypeError, "Member \"delegatecall\" not found or not visible after argument-dependent lookup in contract");
 }
 
+BOOST_AUTO_TEST_CASE(emit_events)
+{
+	char const* text = R"(
+		contract C {
+			event e();
+			function f() public {
+				emit e();
+			}
+		}
+	)";
+	CHECK_SUCCESS_NO_WARNINGS(text);
+	text = R"(
+		contract C {
+			event e(uint a, string b);
+			function f() public {
+				emit e(2, "abc");
+				emit e({b: "abc", a: 8});
+			}
+		}
+	)";
+	CHECK_SUCCESS_NO_WARNINGS(text);
+	text = R"(
+		contract A { event e(uint a, string b); }
+		contract C is A {
+			function f() public {
+				emit A.e(2, "abc");
+				emit A.e({b: "abc", a: 8});
+			}
+		}
+	)";
+	CHECK_SUCCESS_NO_WARNINGS(text);
+}
+
+BOOST_AUTO_TEST_CASE(old_style_events_050)
+{
+	char const* text = R"(
+		contract C {
+			event e();
+			function f() public {
+				e();
+			}
+		}
+	)";
+	CHECK_WARNING(text, "without \"emit\" prefix");
+	text = R"(
+		pragma experimental "v0.5.0";
+		contract C {
+			event e();
+			function f() public {
+				e();
+			}
+		}
+	)";
+	CHECK_ERROR(text, TypeError, "have to be prefixed");
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }
diff --git a/test/libsolidity/SolidityParser.cpp b/test/libsolidity/SolidityParser.cpp
index 861e6408..b7097d0f 100644
--- a/test/libsolidity/SolidityParser.cpp
+++ b/test/libsolidity/SolidityParser.cpp
@@ -1708,6 +1708,19 @@ BOOST_AUTO_TEST_CASE(newInvalidTypeName)
 	CHECK_PARSE_ERROR(text, "Expected explicit type name");
 }
 
+BOOST_AUTO_TEST_CASE(emitWithoutEvent)
+{
+	char const* text = R"(
+		contract C {
+			event A();
+			function f() {
+				emit A;
+			}
+		}
+	)";
+	CHECK_PARSE_ERROR(text, "Expected token LParen got 'Semicolon'");
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }