Code generation for errors.

test/libsolidity/semanticTests/errors/error_in_library_and_interface.sol

@@ -0,0 +1,24 @@
+error E(uint a);
+library L {
+    error E(uint a, uint b);
+}
+interface I {
+    error E(uint a, uint b, uint c);
+}
+contract C {
+    function f() public pure {
+        revert E(1);
+    }
+    function g() public pure {
+        revert L.E(1, 2);
+    }
+    function h() public pure {
+        revert I.E(1, 2, 3);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000001"
+// g() -> FAILURE, hex"85208890", hex"0000000000000000000000000000000000000000000000000000000000000001", hex"0000000000000000000000000000000000000000000000000000000000000002"
+// h() -> FAILURE, hex"7924ea7c", hex"0000000000000000000000000000000000000000000000000000000000000001", hex"0000000000000000000000000000000000000000000000000000000000000002", hex"0000000000000000000000000000000000000000000000000000000000000003"

test/libsolidity/semanticTests/errors/named_error_args.sol

@@ -0,0 +1,10 @@
+error E(uint a, uint b);
+contract C {
+    function f() public pure {
+        revert E({b: 7, a: 2});
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE, hex"85208890", hex"0000000000000000000000000000000000000000000000000000000000000002", hex"0000000000000000000000000000000000000000000000000000000000000007"

test/libsolidity/semanticTests/errors/revert_conversion.sol

@@ -0,0 +1,12 @@
+error E(string a, uint[] b);
+contract C {
+    uint[] x;
+    function f() public {
+        x.push(7);
+        revert E("abc", x);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE, hex"59e4d4df", 0x40, 0x80, 3, "abc", 1, 7

test/libsolidity/semanticTests/errors/simple.sol

@@ -0,0 +1,10 @@
+error E(uint a, uint b);
+contract C {
+    function f() public pure {
+        revert E(2, 7);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE, hex"85208890", 2, 7

test/libsolidity/semanticTests/errors/via_contract_type.sol

@@ -0,0 +1,18 @@
+contract A {
+  error E(uint);
+}
+contract X {
+  error E(string);
+}
+contract B is A {
+  function f() public pure { revert E(1); }
+  function g() public pure  { revert A.E(1); }
+  function h() public pure { revert X.E("abc"); }
+
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000001"
+// g() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000001"
+// h() -> FAILURE, hex"3e9992c9", hex"0000000000000000000000000000000000000000000000000000000000000020", hex"0000000000000000000000000000000000000000000000000000000000000003", hex"6162630000000000000000000000000000000000000000000000000000000000"

test/libsolidity/semanticTests/errors/via_import.sol

@@ -0,0 +1,25 @@
+==== Source: s1.sol ====
+error E(uint);
+==== Source: s2.sol ====
+import "s1.sol" as S;
+==== Source: s3.sol ====
+import "s1.sol" as S;
+import "s2.sol" as T;
+import "s1.sol";
+contract C {
+  function x() public pure {
+    revert E(1);
+  }
+  function y() public pure {
+    revert S.E(2);
+  }
+  function z() public pure {
+    revert T.S.E(3);
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// x() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000001"
+// y() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000002"
+// z() -> FAILURE, hex"002ff067", hex"0000000000000000000000000000000000000000000000000000000000000003"

test/libsolidity/semanticTests/errors/weird_name.sol

@@ -0,0 +1,10 @@
+error error(uint a);
+contract C {
+    function f() public pure {
+        revert error(2);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE, hex"b48fb6cf", hex"0000000000000000000000000000000000000000000000000000000000000002"

test/libsolidity/semanticTests/reverts/error_struct.sol

@@ -0,0 +1,17 @@
+struct error { uint error; }
+contract C {
+	error test();
+	error _struct;
+	function f() public {
+		revert test();
+	}
+	function g(uint x) public returns (uint) {
+		_struct.error = x;
+		return _struct.error;
+	}
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE, hex"f8a8fd6d"
+// g(uint256): 7 -> 7