module: assert that require() is called with a string

as requested in #4577

lib/module.js

@@ -359,6 +359,7 @@ Module.prototype.load = function(filename) {
 
 
 Module.prototype.require = function(path) {
+  assert(typeof path === 'string', 'path must be a string');
   assert(path, 'missing path');
   return Module._load(path, this);
 };

test/simple/test-module-loading.js

@@ -295,3 +295,12 @@ process.on('exit', function() {
 // #1440 Loading files with a byte order marker.
 assert.equal(42, require('../fixtures/utf8-bom.js'));
 assert.equal(42, require('../fixtures/utf8-bom.json'));
+
+// require() must take string, and must be truthy
+assert.throws(function() {
+  require({ foo: 'bar' });
+}, 'path must be a string');
+
+assert.throws(function() {
+  require(false);
+}, 'missing path');