Merge pull request #9326 from ethereum/eventOverwriting

[BREAKING] Disallow multiple events with same name and types.

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 parameter types 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 parameter types 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 parameter types 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 parameter types 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 parameter types defined twice.

test/libsolidity/syntaxTests/events/multiple_inheritance.sol

@@ -0,0 +1,4 @@
+contract A { event X(uint); }
+contract B is A {}
+contract C is A {}
+contract D is B, C {}

test/libsolidity/syntaxTests/events/overloading_in_contract.sol

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