Syntax for custom errors.

test/libsolidity/semanticTests/error/selector.sol

@@ -0,0 +1,20 @@
+library L {
+    error E();
+}
+library S {
+    error E(uint);
+}
+library T {
+    error E();
+}
+contract C {
+    function f() public pure returns (bytes4, bytes4) {
+        assert(L.E.selector == T.E.selector);
+        assert(L.E.selector != S.E.selector);
+        return (L.E.selector, S.E.selector);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> 0x92bbf6e800000000000000000000000000000000000000000000000000000000, 0x2ff06700000000000000000000000000000000000000000000000000000000

test/libsolidity/syntaxTests/errors/abi_decode_error.sol

@@ -0,0 +1,9 @@
+error E(uint);
+contract C {
+    function f() public pure returns (bytes memory) {
+        return abi.decode(msg.data, (E));
+    }
+}
+// ----
+// TypeError 1039: (119-120): Argument has to be a type name.
+// TypeError 5132: (90-122): Different number of arguments in return statement than in returns declaration.

test/libsolidity/syntaxTests/errors/abi_encode_error.sol

@@ -0,0 +1,8 @@
+error E(uint);
+contract C {
+    function f() public pure returns (bytes memory) {
+        return abi.encode(E);
+    }
+}
+// ----
+// TypeError 2056: (108-109): This type cannot be encoded.

test/libsolidity/syntaxTests/errors/abi_encode_error_instance.sol

@@ -0,0 +1,8 @@
+error E(uint);
+contract C {
+    function f() public pure returns (bytes memory) {
+        return abi.encode(E(2));
+    }
+}
+// ----
+// TypeError 2056: (108-112): This type cannot be encoded.

test/libsolidity/syntaxTests/errors/all_ones_signature.sol

@@ -0,0 +1,8 @@
+error test266151307();
+contract C {
+    error test266151307();
+}
+// ----
+// Warning 2519: (40-62): This declaration shadows an existing declaration.
+// SyntaxError 2855: (0-22): The selector 0xffffffff is reserved. Please rename the error to avoid the collision.
+// SyntaxError 2855: (40-62): The selector 0xffffffff is reserved. Please rename the error to avoid the collision.

test/libsolidity/syntaxTests/errors/anonymous.sol

@@ -0,0 +1,3 @@
+error E() anonymous;
+// ----
+// ParserError 2314: (10-19): Expected ';' but got 'anonymous'

test/libsolidity/syntaxTests/errors/assert_with_cond_and_error.sol

@@ -0,0 +1,6 @@
+error E();
+function f(bool x) pure {
+    assert(x, E());
+}
+// ----
+// TypeError 6160: (41-55): Wrong argument count for function call: 2 arguments given but expected 1.

test/libsolidity/syntaxTests/errors/assert_with_error.sol

@@ -0,0 +1,6 @@
+error E();
+function f() pure {
+    assert(E());
+}
+// ----
+// TypeError 9553: (42-45): Invalid type for argument in function call. Invalid implicit conversion from tuple() to bool requested.

test/libsolidity/syntaxTests/errors/basic.sol

@@ -0,0 +1,6 @@
+contract C {
+    error MyError();
+    error MyError2(uint x);
+    error MyError3(uint x, bytes);
+}
+// ----

test/libsolidity/syntaxTests/errors/clash_function_error.sol

@@ -0,0 +1,4 @@
+function Err() pure {}
+error Err();
+// ----
+// DeclarationError 2333: (23-35): Identifier already declared.

test/libsolidity/syntaxTests/errors/clash_function_error_inheritance.sol

@@ -0,0 +1,4 @@
+contract A { function Err() public pure {} }
+contract B is A { error Err(); }
+// ----
+// DeclarationError 9097: (63-75): Identifier already declared.

test/libsolidity/syntaxTests/errors/clash_function_error_inheritance_2.sol

@@ -0,0 +1,5 @@
+contract A { function Err() public pure {} }
+contract B { error Err(); }
+contract C is A, B {}
+// ----
+// DeclarationError 9097: (58-70): Identifier already declared.

test/libsolidity/syntaxTests/errors/error_address_payable.sol

@@ -0,0 +1,2 @@
+error E(address payable x);
+// ----

test/libsolidity/syntaxTests/errors/error_as_function_param.sol

@@ -0,0 +1,4 @@
+error E(uint);
+function f(E x) pure returns (uint) {}
+// ----
+// TypeError 5172: (26-27): Name has to refer to a struct, enum or contract.

test/libsolidity/syntaxTests/errors/error_in_interface.sol

@@ -0,0 +1,4 @@
+interface C {
+    error E(uint);
+}
+// ----

test/libsolidity/syntaxTests/errors/error_in_library.sol

@@ -0,0 +1,4 @@
+library L {
+    error E(uint);
+}
+// ----

test/libsolidity/syntaxTests/errors/error_location_memory.sol

@@ -0,0 +1,3 @@
+error E(uint[] memory);
+// ----
+// ParserError 2314: (15-21): Expected ',' but got 'memory'

test/libsolidity/syntaxTests/errors/error_location_specifier.sol

@@ -0,0 +1,3 @@
+error E(uint[] calldata);
+// ----
+// ParserError 2314: (15-23): Expected ',' but got 'calldata'

test/libsolidity/syntaxTests/errors/error_reserved_name.sol

@@ -0,0 +1,3 @@
+error Error(uint);
+// ----
+// SyntaxError 1855: (0-18): The built-in errors "Error" and "Panic" cannot be re-defined.

test/libsolidity/syntaxTests/errors/file_level.sol

@@ -0,0 +1,6 @@
+error MyError();
+error MyError2(uint x);
+contract C {
+    error MyError3(uint x, bytes);
+}
+// ----

test/libsolidity/syntaxTests/errors/hash_collision.sol

@@ -0,0 +1,6 @@
+contract test {
+    error gsf();
+    error tgeo();
+}
+// ----
+// TypeError 4883: (0-52): Error signature hash collision for tgeo()

test/libsolidity/syntaxTests/errors/indexed_error.sol

@@ -0,0 +1,3 @@
+error E(uint indexed);
+// ----
+// ParserError 2314: (13-20): Expected ',' but got 'indexed'

test/libsolidity/syntaxTests/errors/no_mappings.sol

@@ -0,0 +1,9 @@
+error MyError(mapping(uint => uint));
+contract C {
+    error MyError2(mapping(uint => uint));
+}
+// ----
+// TypeError 3448: (14-35): Type containing a (nested) mapping is not allowed as error parameter type.
+// TypeError 3417: (14-35): Internal or recursive type is not allowed as error parameter type.
+// TypeError 3448: (70-91): Type containing a (nested) mapping is not allowed as error parameter type.
+// TypeError 3417: (70-91): Internal or recursive type is not allowed as error parameter type.

test/libsolidity/syntaxTests/errors/no_overloading.sol

@@ -0,0 +1,4 @@
+error Err(uint);
+error Err(bytes32);
+// ----
+// DeclarationError 2333: (17-36): Identifier already declared.

test/libsolidity/syntaxTests/errors/no_overloading_inheritance.sol

@@ -0,0 +1,8 @@
+contract A {
+    error Err(uint);
+}
+contract B is A {
+    error Err(bytes32);
+}
+// ----
+// DeclarationError 9097: (58-77): Identifier already declared.

test/libsolidity/syntaxTests/errors/no_structs_in_abiv1.sol

@@ -0,0 +1,7 @@
+pragma abicoder v1;
+struct S {uint a;}
+contract C {
+    error MyError(S);
+}
+// ----
+// TypeError 3061: (70-71): This type is only supported in ABI coder v2. Use "pragma abicoder v2;" to enable the feature.

test/libsolidity/syntaxTests/errors/panic_reserved_name.sol

@@ -0,0 +1,3 @@
+error Panic(bytes2);
+// ----
+// SyntaxError 1855: (0-20): The built-in errors "Error" and "Panic" cannot be re-defined.

test/libsolidity/syntaxTests/errors/selector.sol

@@ -0,0 +1,6 @@
+error E();
+
+contract C {
+    bytes4 t = E.selector;
+}
+// ----

test/libsolidity/syntaxTests/errors/selector_on_instance.sol

@@ -0,0 +1,7 @@
+error E();
+
+contract C {
+    bytes4 t = E().selector;
+}
+// ----
+// TypeError 9582: (40-52): Member "selector" not found or not visible after argument-dependent lookup in tuple().

test/libsolidity/syntaxTests/errors/struct_named_error.sol

@@ -0,0 +1,6 @@
+// Test that the parser workaround is not breaking.
+struct error {uint a;}
+contract C {
+    error x;
+}
+// ----

test/libsolidity/syntaxTests/errors/using.sol

@@ -0,0 +1,12 @@
+error E(uint);
+library L {
+    function f(uint) internal {}
+}
+contract C {
+    using L for *;
+    function f() public pure {
+        E.f();
+    }
+}
+// ----
+// TypeError 9582: (133-136): Member "f" not found or not visible after argument-dependent lookup in function (uint256) pure.

test/libsolidity/syntaxTests/errors/using_2.sol

@@ -0,0 +1,12 @@
+error E(uint);
+library L {
+    function f(uint) internal {}
+}
+contract C {
+    using L for E;
+    function f() public pure {
+        E.f();
+    }
+}
+// ----
+// TypeError 5172: (91-92): Name has to refer to a struct, enum or contract.

test/libsolidity/syntaxTests/errors/using_structs.sol

@@ -0,0 +1,6 @@
+struct S {uint a;}
+contract C {
+    error MyError(S);
+    error MyError2(S t);
+}
+// ----

test/libsolidity/syntaxTests/errors/weird1.sol

@@ -0,0 +1,7 @@
+error E();
+
+contract C {
+    function() internal pure x = E;
+}
+// ----
+// TypeError 7407: (58-59): Type function () pure is not implicitly convertible to expected type function () pure. Special functions can not be converted to function types.

test/libsolidity/syntaxTests/errors/weird3.sol

@@ -0,0 +1,7 @@
+error E();
+
+contract C {
+    E x;
+}
+// ----
+// TypeError 5172: (29-30): Name has to refer to a struct, enum or contract.

test/libsolidity/syntaxTests/errors/weird4.sol

@@ -0,0 +1,9 @@
+error E();
+
+contract C {
+    function f() public pure {
+        E x;
+    }
+}
+// ----
+// TypeError 5172: (64-65): Name has to refer to a struct, enum or contract.

test/libsolidity/syntaxTests/errors/zero_signature.sol

@@ -0,0 +1,8 @@
+error buyAndFree22457070633(uint256);
+contract C {
+    error buyAndFree22457070633(uint256);
+}
+// ----
+// Warning 2519: (55-92): This declaration shadows an existing declaration.
+// SyntaxError 2855: (0-37): The selector 0x00000000 is reserved. Please rename the error to avoid the collision.
+// SyntaxError 2855: (55-92): The selector 0x00000000 is reserved. Please rename the error to avoid the collision.