Check in codegen test expectations.

test/codegen/expect/corelib/reg_exp4_test.js

+dart_library.library('corelib/reg_exp4_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__reg_exp4_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const reg_exp4_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  reg_exp4_test.main = function() {
+    try {
+      let ex = core.RegExp.new(null);
+      expect$.Expect.fail("Expected: ArgumentError got: no exception");
+    } catch (ex) {
+      if (!core.ArgumentError.is(ex)) {
+        expect$.Expect.fail(dart.str`Expected: ArgumentError got: ${ex}`);
+      }
+    }
+
+    try {
+      core.RegExp.new("^\\w+$").hasMatch(null);
+      expect$.Expect.fail("Expected: ArgumentError got: no exception");
+    } catch (ex) {
+      if (!core.ArgumentError.is(ex)) {
+        expect$.Expect.fail(dart.str`Expected: ArgumentError got: ${ex}`);
+      }
+    }
+
+    try {
+      core.RegExp.new("^\\w+$").firstMatch(null);
+      expect$.Expect.fail("Expected: ArgumentError got: no exception");
+    } catch (ex) {
+      if (!core.ArgumentError.is(ex)) {
+        expect$.Expect.fail(dart.str`Expected: ArgumentError got: ${ex}`);
+      }
+    }
+
+    try {
+      core.RegExp.new("^\\w+$").allMatches(null);
+      expect$.Expect.fail("Expected: ArgumentError got: no exception");
+    } catch (ex) {
+      if (!core.ArgumentError.is(ex)) {
+        expect$.Expect.fail(dart.str`Expected: ArgumentError got: ${ex}`);
+      }
+    }
+
+    try {
+      core.RegExp.new("^\\w+$").stringMatch(null);
+      expect$.Expect.fail("Expected: ArgumentError got: no exception");
+    } catch (ex) {
+      if (!core.ArgumentError.is(ex)) {
+        expect$.Expect.fail(dart.str`Expected: ArgumentError got: ${ex}`);
+      }
+    }
+
+  };
+  dart.fn(reg_exp4_test.main, VoidTodynamic());
+  // Exports:
+  exports.reg_exp4_test = reg_exp4_test;
+});