Warn about using events without emit.

2 files changed, 13 insertions, 1 deletions

diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index d93ebbd1..2914472a 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -961,7 +961,8 @@ void TypeChecker::endVisit(EmitStatement const& _emit)
 		_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.");
+		m_errorReporter.typeError(_emit.eventCall().expression().location(), "Expression has to be an event invocation.");
+	m_insideEmitStatement = false;
 }
 
 bool TypeChecker::visit(VariableDeclarationStatement const& _statement)
@@ -1540,6 +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 fc4ec6f0..16796b63 100644
--- a/libsolidity/analysis/TypeChecker.h
+++ b/libsolidity/analysis/TypeChecker.h
@@ -94,6 +94,7 @@ 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;
@@ -131,6 +132,9 @@ private:
 
 	ContractDefinition const* m_scope = nullptr;
 
+	/// Flag indicating whether we are currently inside an EmitStatement.
+	bool m_insideEmitStatement = false;
+
 	ErrorReporter& m_errorReporter;
 };