Merge branch 'solc-0.7' into solc-0.8

contracts/introspection/ERC165.sol

@@ -32,7 +32,7 @@ abstract contract ERC165 is IERC165 {
      *
      * Time complexity O(1), guaranteed to always use less than 30 000 gas.
      */
-    function supportsInterface(bytes4 interfaceId) public view override returns (bool) {
+    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
         return _supportedInterfaces[interfaceId];
     }
 

contracts/introspection/ERC165Checker.sol

@@ -40,6 +40,29 @@ library ERC165Checker {
             _supportsERC165Interface(account, interfaceId);
     }
 
+    /**
+     * @dev Returns a boolean array where each value corresponds to the
+     * interfaces passed in and whether they're supported or not. This allows
+     * you to batch check interfaces for a contract where your expectation
+     * is that some interfaces may not be supported.
+     *
+     * See {IERC165-supportsInterface}.
+     */
+    function getSupportedInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool[] memory) {
+        // an array of booleans corresponding to interfaceIds and whether they're supported or not
+        bool[] memory interfaceIdsSupported = new bool[](interfaceIds.length);
+
+        // query support of ERC165 itself
+        if (supportsERC165(account)) {
+            // query support of each interface in interfaceIds
+            for (uint256 i = 0; i < interfaceIds.length; i++) {
+                interfaceIdsSupported[i] = _supportsERC165Interface(account, interfaceIds[i]);
+            }
+        }
+
+        return interfaceIdsSupported;
+    }
+
     /**
      * @dev Returns true if `account` supports all the interfaces defined in
      * `interfaceIds`. Support for {IERC165} itself is queried automatically.

contracts/introspection/ERC1820Implementer.sol

@@ -20,7 +20,7 @@ contract ERC1820Implementer is IERC1820Implementer {
     /**
      * See {IERC1820Implementer-canImplementInterfaceForAddress}.
      */
-    function canImplementInterfaceForAddress(bytes32 interfaceHash, address account) public view override returns (bytes32) {
+    function canImplementInterfaceForAddress(bytes32 interfaceHash, address account) public view virtual override returns (bytes32) {
         return _supportedInterfaces[interfaceHash][account] ? _ERC1820_ACCEPT_MAGIC : bytes32(0x00);
     }