Fix additional spec violations wrt RegExp.lastIndex.

test/mjsunit/regress/regress-2437.js

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+// Summary of the spec: lastIndex is reset to 0 if
+// - a regexp fails to match, regardless of global or non-global.
+// - a global regexp is used in a function that returns multiple results,
+//   such as String.prototype.replace or String.prototype.match, since it
+//   repeats the regexp until it fails to match.
+// Otherwise lastIndex is only set when a global regexp matches, to the index
+// after the match.
+
 // Test Regexp.prototype.exec
 r = /a/;
 r.lastIndex = 1;
 r.exec("zzzz");
 assertEquals(0, r.lastIndex);
 
 // Test Regexp.prototype.test
 r = /a/;
 r.lastIndex = 1;
 r.test("zzzz");
@@ skipping 28 matching lines @@
 r.lastIndex = 1;
 "zzzz".replace(r, "a");
 assertEquals(0, r.lastIndex);
 
 // Test String.prototype.replace with replacement function
 r = /a/;
 r.lastIndex = 1;
 "zzzz".replace(r, function() { return ""; });
 assertEquals(0, r.lastIndex);
 
+// Regexp functions that returns multiple results:
+// A global regexp always resets lastIndex regardless of whether it matches.
+r = /a/g;
+r.lastIndex = -1;
+"0123abcd".replace(r, "x");
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = -1;
+"01234567".replace(r, "x");
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = -1;
+"0123abcd".match(r);
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = -1;
+"01234567".match(r);
+assertEquals(0, r.lastIndex);
+
+// A non-global regexp resets lastIndex iff it does not match.
+r = /a/;
+r.lastIndex = -1;
+"0123abcd".replace(r, "x");
+assertEquals(-1, r.lastIndex);
+
+r.lastIndex = -1;
+"01234567".replace(r, "x");
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = -1;
+"0123abcd".match(r);
+assertEquals(-1, r.lastIndex);
+
+r.lastIndex = -1;
+"01234567".match(r);
+assertEquals(0, r.lastIndex);
+
+// Also test RegExp.prototype.exec and RegExp.prototype.test
+r = /a/g;
+r.lastIndex = 1;
+r.exec("01234567");
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = 1;
+r.exec("0123abcd");
+assertEquals(5, r.lastIndex);
+
+r = /a/;
+r.lastIndex = 1;
+r.exec("01234567");
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = 1;
+r.exec("0123abcd");
+assertEquals(1, r.lastIndex);
+
+r = /a/g;
+r.lastIndex = 1;
+r.test("01234567");
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = 1;
+r.test("0123abcd");
+assertEquals(5, r.lastIndex);
+
+r = /a/;
+r.lastIndex = 1;
+r.test("01234567");
+assertEquals(0, r.lastIndex);
+
+r.lastIndex = 1;
+r.test("0123abcd");
+assertEquals(1, r.lastIndex);