Display human readable type name in conversion error message

test/libsolidity/syntaxTests/conversion/explicit_conversion_error_to_bytes4.sol

@@ -0,0 +1,11 @@
+interface MyInterface {
+    error MyCustomError(uint256, bool);
+}
+
+contract Test {
+    function test() public returns(bytes4) {
+        return bytes4(MyInterface.MyCustomError);
+    }
+}
+// ----
+// TypeError 9640: (143-176): Explicit type conversion not allowed from "error MyCustomError(uint256,bool)" to "bytes4".

test/libsolidity/syntaxTests/conversion/explicit_conversion_event_to_bytes4.sol

@@ -0,0 +1,9 @@
+contract Test {
+    event MyCustomEvent(uint256);
+
+    function test() public returns(bytes4) {
+        return bytes4(MyCustomEvent);
+    }
+}
+// ----
+// TypeError 9640: (111-132): Explicit type conversion not allowed from "event MyCustomEvent(uint256)" to "bytes4".

test/libsolidity/syntaxTests/conversion/explicit_conversion_from_error.sol

@@ -0,0 +1,28 @@
+interface MyInterface {
+    enum MyEnum { E1, E2 }
+    error CustomError1(
+        uint256,
+        bool,
+        bool[],
+        address payable,
+        MyInterface,
+        MyEnum,
+        function (string memory) external returns (uint)
+    );
+}
+
+contract Test {
+    function testFunction(string memory) external returns (uint) {}
+
+    function test() public {
+        MyInterface instance = MyInterface(msg.sender);
+        bool[] calldata arr;
+        address payable addr;
+        bytes4(MyInterface.CustomEror1);
+        bytes4(MyInterface.CustomError1());
+        bytes4(MyInterface.CustomError1(1, true, arr, addr, instance, MyInterface.MyEnum.E1, this.testFunction));
+        address(MyInterface.CustomError1);
+    }
+}
+// ----
+// TypeError 9582: (495-518): Member "CustomEror1" not found or not visible after argument-dependent lookup in type(contract MyInterface).

test/libsolidity/syntaxTests/conversion/explicit_conversion_from_event.sol

@@ -0,0 +1,34 @@
+interface MyInterface {
+    enum MyEnum { E1, E2 }
+}
+
+contract Test {
+    function testFunction(string memory) external returns (uint) {}
+
+    event CustomEvent1(
+        uint256,
+        bool,
+        bool[],
+        address payable,
+        MyInterface,
+        MyInterface.MyEnum,
+        function (string memory) external returns (uint)
+    );
+
+
+    function test() public {
+        MyInterface instance = MyInterface(msg.sender);
+        bool[] calldata arr;
+        address payable addr;
+        bytes4(CustomEvent1);
+        bytes4(CustomEvent1());
+        bytes4(CustomEvent1(1, true, arr, addr, instance, MyInterface.MyEnum.E1, this.testFunction));
+        address(CustomEvent1);
+    }
+}
+// ----
+// TypeError 9640: (502-522): Explicit type conversion not allowed from "event CustomEvent1(uint256,bool,bool[],address payable,contract MyInterface,enum MyInterface.MyEnum,function (string) external returns (uint256))" to "bytes4".
+// TypeError 6160: (539-553): Wrong argument count for function call: 0 arguments given but expected 7.
+// TypeError 9640: (532-554): Explicit type conversion not allowed from "tuple()" to "bytes4".
+// TypeError 9640: (564-656): Explicit type conversion not allowed from "tuple()" to "bytes4".
+// TypeError 9640: (666-687): Explicit type conversion not allowed from "event CustomEvent1(uint256,bool,bool[],address payable,contract MyInterface,enum MyInterface.MyEnum,function (string) external returns (uint256))" to "address".