Disallow multiple events with same name and types.

Changelog.md

@@ -10,6 +10,7 @@ Breaking changes:
  * Type Checker: Exponentiation and shifts of literals by non-literals will always use ``uint256`` or ``int256`` as a type.
  * Type Checker: Disallow structs and arrays in memory or calldata if they contain nested mappings.
  * Type Checker: Disallow assignments to state variables that contain nested mappings.
+ * Type checker: Disallow events with same name and parameter types in inheritance hierarchy.
 
 Language Features:
  * Yul: Disallow EVM instruction `pc()`.

libsolidity/analysis/ContractLevelChecker.cpp

@@ -120,8 +120,9 @@ void ContractLevelChecker::checkDuplicateEvents(ContractDefinition const& _contr
 	/// Checks that two events with the same name defined in this contract have different
 	/// argument types
 	map<string, vector<EventDefinition const*>> events;
-	for (EventDefinition const* event: _contract.events())
-		events[event->name()].push_back(event);
+	for (auto const* contract: _contract.annotation().linearizedBaseContracts)
+		for (EventDefinition const* event: contract->events())
+			events[event->name()].push_back(event);
 
 	findDuplicateDefinitions(events);
 }

test/libsolidity/syntaxTests/events/inheritance_adds_anonymous.sol

@@ -0,0 +1,8 @@
+contract A {
+    event X();
+}
+contract B is A {
+    event X() anonymous;
+}
+// ----
+// DeclarationError 5883: (52-72): Event with same name and arguments defined twice.

test/libsolidity/syntaxTests/events/inheritance_adds_indexed.sol

@@ -0,0 +1,8 @@
+contract A {
+    event X(uint);
+}
+contract B is A {
+    event X(uint indexed);
+}
+// ----
+// DeclarationError 5883: (56-78): Event with same name and arguments defined twice.

test/libsolidity/syntaxTests/events/inheritance_adds_parameter.sol

@@ -0,0 +1,6 @@
+contract A {
+    event X();
+}
+contract B is A {
+    event X(uint);
+}

test/libsolidity/syntaxTests/events/inheritance_event_repeated.sol

@@ -0,0 +1,8 @@
+contract A {
+    event X(uint);
+}
+contract B is A {
+    event X(uint);
+}
+// ----
+// DeclarationError 5883: (56-70): Event with same name and arguments defined twice.

test/libsolidity/syntaxTests/events/inheritance_multi_parent.sol

@@ -0,0 +1,10 @@
+contract A {
+    event X(uint, uint indexed);
+}
+contract B {
+    event X(uint, uint);
+}
+contract C is A, B {
+}
+// ----
+// DeclarationError 5883: (65-85): Event with same name and arguments defined twice.

test/libsolidity/syntaxTests/events/inheritance_removes_indexed.sol

@@ -0,0 +1,8 @@
+contract A {
+    event X(uint, uint indexed);
+}
+contract B is A {
+    event X(uint, uint);
+}
+// ----
+// DeclarationError 5883: (70-90): Event with same name and arguments defined twice.

test/libsolidity/syntaxTests/events/overloading_in_contract.sol

@@ -0,0 +1,5 @@
+contract A {
+    event X();
+    event X(uint);
+}
+// ----