Disallow private functions from being overridden

Changelog.md

@@ -1,3 +1,8 @@
+### 0.5.17 (2020-03-17)
+
+Bugfixes:
+ * Type Checker: Disallow overriding of private functions.
+
 ### 0.5.16 (2020-01-02)
 
 Bugfixes:

docs/bugs_by_version.json

@@ -782,6 +782,10 @@
         "bugs": [],
         "released": "2020-01-02"
     },
+    "0.5.17": {
+        "bugs": [],
+        "released": "2020-03-17"
+    },
     "0.5.2": {
         "bugs": [
             "SignedArrayStorageCopy",

libsolidity/analysis/ContractLevelChecker.cpp

@@ -203,6 +203,9 @@ void ContractLevelChecker::checkFunctionOverride(FunctionDefinition const& _func
 			stateMutabilityToString(_function.stateMutability()) +
 			"\"."
 		);
+	if (_super.visibility() == Declaration::Visibility::Private)
+		overrideError(_function, _super, "Private functions cannot be overridden.");
+
 }
 
 void ContractLevelChecker::overrideError(FunctionDefinition const& function, FunctionDefinition const& super, string message)

test/externalTests/zeppelin.sh

@@ -31,7 +31,7 @@ function test_fn { npm run test; }
 function zeppelin_test
 {
     OPTIMIZER_LEVEL=1
-    setup https://github.com/OpenZeppelin/openzeppelin-solidity.git master
+    setup https://github.com/OpenZeppelin/openzeppelin-solidity.git v2.5.0
     run_install install_fn
 
     CONFIG="truffle-config.js"

test/libsolidity/syntaxTests/inheritance/override/override_private.sol

@@ -0,0 +1,8 @@
+contract A {
+	function test() private returns (uint256) {}
+}
+contract X is A {
+	function test() private returns (uint256) {}
+}
+// ----
+// TypeError: (80-124): Private functions cannot be overridden.

test/libsolidity/syntaxTests/inheritance/override/override_private1.sol

@@ -0,0 +1,8 @@
+contract A {
+	function test() public returns (uint256) {}
+}
+contract X is A {
+	function test() private returns (uint256) {}
+}
+// ----
+// TypeError: (79-123): Overriding function visibility differs.

test/libsolidity/syntaxTests/inheritance/override/override_private2.sol

@@ -0,0 +1,9 @@
+contract A {
+	function test() private returns (uint256) {}
+}
+contract X is A {
+	function test() public returns (uint256) {}
+}
+// ----
+// TypeError: (80-123): Overriding function visibility differs.
+// TypeError: (80-123): Private functions cannot be overridden.

test/libsolidity/syntaxTests/inheritance/override/override_private_multi.sol

@@ -0,0 +1,11 @@
+contract A {
+	function test() private returns (uint256) {}
+}
+contract B {
+	function test() private returns (uint256) {}
+}
+
+contract X is A, B {
+}
+// ----
+// TypeError: (75-119): Private functions cannot be overridden.

test/libsolidity/syntaxTests/inheritance/override/override_private_multi1.sol

@@ -0,0 +1,11 @@
+contract A {
+	function test() public returns (uint256) {}
+}
+contract B {
+	function test() private returns (uint256) {}
+}
+
+contract X is A, B {
+}
+// ----
+// TypeError: (74-118): Overriding function visibility differs.

test/libsolidity/syntaxTests/inheritance/override/override_private_multi2.sol

@@ -0,0 +1,12 @@
+contract A {
+	function test() private returns (uint256) {}
+}
+contract B {
+	function test() public returns (uint256) {}
+}
+
+contract X is A, B {
+}
+// ----
+// TypeError: (75-118): Overriding function visibility differs.
+// TypeError: (75-118): Private functions cannot be overridden.

test/solcjsTests.sh

@@ -58,6 +58,7 @@ DIR=$(mktemp -d)
     npm version --allow-same-version --no-git-tag-version $VERSION
 
     echo "Running solc-js tests..."
+    sed -i -e 's/latest/v0.5.0+commit.1d4f565a/' test/package.js
     npm run test
 )
 rm -rf "$DIR"