Revert statement.

test/libsolidity/semanticTests/errors/panic_via_import.sol

@@ -0,0 +1,18 @@
+==== Source: s1.sol ====
+error E(uint);
+==== Source: s2.sol ====
+import { E as Panic } from "s1.sol";
+contract C {
+    error E(uint);
+    function a() public pure {
+        revert Panic(1);
+    }
+    function b() public pure {
+        revert E(1);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// a() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000001"
+// b() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000001"

test/libsolidity/semanticTests/errors/using_structs.sol

@@ -0,0 +1,20 @@
+pragma abicoder v2;
+struct S { uint a; string b; }
+error E(uint a, S s, uint b);
+contract C {
+    S s;
+    function f(bool c) public {
+        if (c) {
+            s.a = 9;
+            s.b = "abc";
+            revert E(2, s, 7);
+        } else {
+            revert E({b: 7, a: 2, s: S({b: "abc", a: 9})});
+        }
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f(bool): true -> FAILURE, hex"e96e07f0", hex"0000000000000000000000000000000000000000000000000000000000000002", hex"0000000000000000000000000000000000000000000000000000000000000060", hex"0000000000000000000000000000000000000000000000000000000000000007", hex"0000000000000000000000000000000000000000000000000000000000000009", hex"0000000000000000000000000000000000000000000000000000000000000040", hex"0000000000000000000000000000000000000000000000000000000000000003", hex"6162630000000000000000000000000000000000000000000000000000000000"
+// f(bool): false -> FAILURE, hex"e96e07f0", hex"0000000000000000000000000000000000000000000000000000000000000002", hex"0000000000000000000000000000000000000000000000000000000000000060", hex"0000000000000000000000000000000000000000000000000000000000000007", hex"0000000000000000000000000000000000000000000000000000000000000009", hex"0000000000000000000000000000000000000000000000000000000000000040", hex"0000000000000000000000000000000000000000000000000000000000000003", hex"6162630000000000000000000000000000000000000000000000000000000000"

test/libsolidity/syntaxTests/errors/require_custom.sol

@@ -0,0 +1,8 @@
+error E(uint a, uint b);
+contract C {
+    function f(bool c) public pure {
+        require(c, E(2, 7));
+    }
+}
+// ----
+// TypeError 9322: (83-90): No matching declaration found after argument-dependent lookup.

test/libsolidity/syntaxTests/errors/revert_parentheses.sol

@@ -0,0 +1,8 @@
+error E(uint a, uint b);
+contract C {
+    function f() public pure {
+        revert(E(2, 7));
+    }
+}
+// ----
+// TypeError 9322: (77-83): No matching declaration found after argument-dependent lookup.

test/libsolidity/syntaxTests/revertStatement/at_file_level.sol

@@ -0,0 +1,3 @@
+revert X();
+// ----
+// ParserError 2314: (8-9): Expected ';' but got '('

test/libsolidity/syntaxTests/revertStatement/error_used_elsewhere.sol

@@ -0,0 +1,6 @@
+error E();
+function f() pure {
+    E();
+}
+// ----
+// TypeError 7757: (35-38): Errors can only be used with revert statements: "revert MyError();".

test/libsolidity/syntaxTests/revertStatement/in_global_function.sol

@@ -0,0 +1,4 @@
+error E();
+function f() pure {
+    revert E();
+}

test/libsolidity/syntaxTests/revertStatement/non_called.sol

@@ -0,0 +1,6 @@
+error E();
+function f() public pure {
+    revert E;
+}
+// ----
+// ParserError 2314: (50-51): Expected '(' but got ';'

test/libsolidity/syntaxTests/revertStatement/non_error.sol

@@ -0,0 +1,5 @@
+function f() public pure {
+    revert 1;
+}
+// ----
+// ParserError 2314: (38-39): Expected ';' but got 'Number'

test/libsolidity/syntaxTests/revertStatement/regular.sol

@@ -0,0 +1,6 @@
+error E();
+contract C {
+    function f() public pure {
+        revert E();
+    }
+}

test/libsolidity/syntaxTests/revertStatement/revert_event.sol

@@ -0,0 +1,8 @@
+contract C {
+    event E();
+    function f() public pure {
+        revert E();
+    }
+}
+// ----
+// TypeError 1885: (74-75): Expression has to be an error.

test/libsolidity/syntaxTests/revertStatement/revert_revert.sol

@@ -0,0 +1,8 @@
+error revert();
+contract C {
+    function f() public pure {
+        revert revert();
+    }
+}
+// ----
+// Warning 2319: (0-15): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/revertStatement/scoped.sol

@@ -0,0 +1,8 @@
+contract A {
+    error E();
+}
+contract C {
+    function f() public pure {
+        revert A.E();
+    }
+}

test/libsolidity/syntaxTests/revertStatement/using_function.sol

@@ -0,0 +1,9 @@
+error f(uint, uint);
+contract C {
+    function f(uint) public {
+        revert f(10);
+    }
+}
+// ----
+// Warning 2519: (38-91): This declaration shadows an existing declaration.
+// TypeError 1885: (79-80): Expression has to be an error.

test/libsolidity/syntaxTests/revertStatement/using_struct.sol

@@ -0,0 +1,8 @@
+struct S { uint x; }
+contract C {
+    function f() public {
+        revert S(10);
+    }
+}
+// ----
+// TypeError 1885: (75-76): Expression has to be an error.