Do not consider shadowing in variable names inside event declarations

3 files changed, 16 insertions, 2 deletions

diff --git a/Changelog.md b/Changelog.md
index 8ebc30d0..ea31095d 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -11,6 +11,7 @@ Bugfixes:
  * Type Checker: Properly support overwriting members inherited from ``address`` in a contract
    (such as ``balance``, ``transfer``, etc.)
  * Type Checker: Prevent duplicate event declarations.
+ * Type Checker: Do not mark event parameters as shadowing state variables.
 
 ### 0.4.17 (2017-09-21)
 
diff --git a/libsolidity/analysis/NameAndTypeResolver.cpp b/libsolidity/analysis/NameAndTypeResolver.cpp
index 523e7176..5d010693 100644
--- a/libsolidity/analysis/NameAndTypeResolver.cpp
+++ b/libsolidity/analysis/NameAndTypeResolver.cpp
@@ -647,10 +647,12 @@ void DeclarationRegistrationHelper::registerDeclaration(Declaration& _declaratio
 
 	bool warnAboutShadowing = true;
 	// Do not warn about shadowing for structs and enums because their members are
-	// not accessible without prefixes.
+	// not accessible without prefixes. Also do not warn about event parameters
+	// because they don't participate in any proper scope.
 	if (
 		dynamic_cast<StructDefinition const*>(m_currentScope) ||
-		dynamic_cast<EnumDefinition const*>(m_currentScope)
+		dynamic_cast<EnumDefinition const*>(m_currentScope) ||
+		dynamic_cast<EventDefinition const*>(m_currentScope)
 	)
 		warnAboutShadowing = false;
 	// Do not warn about the constructor shadowing the contract.
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index ed223678..350d41f1 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -6371,6 +6371,17 @@ BOOST_AUTO_TEST_CASE(function_override_is_not_shadowing)
 	CHECK_SUCCESS_NO_WARNINGS(text);
 }
 
+BOOST_AUTO_TEST_CASE(event_parameter_cannot_shadow_state_variable)
+{
+	char const* text = R"(
+		contract C {
+			address a;
+			event E(address a);
+		}
+	)";
+	CHECK_SUCCESS_NO_WARNINGS(text);
+}
+
 BOOST_AUTO_TEST_CASE(callable_crash)
 {
 	char const* text = R"(