Get a better error for compile(falsy)

lib/handlebars/compiler/compiler.js

@@ -1035,6 +1035,10 @@ Handlebars.JavaScriptCompiler = function() {};
 })(Handlebars.Compiler, Handlebars.JavaScriptCompiler);
 
 Handlebars.precompile = function(string, options) {
+  if (typeof string !== 'string') {
+    throw new Handlebars.Exception("You must pass a string to Handlebars.compile. You passed " + string);
+  }
+
   options = options || {};
 
   var ast = Handlebars.parse(string);
@@ -1043,6 +1047,10 @@ Handlebars.precompile = function(string, options) {
 };
 
 Handlebars.compile = function(string, options) {
+  if (typeof string !== 'string') {
+    throw new Handlebars.Exception("You must pass a string to Handlebars.compile. You passed " + string);
+  }
+
   options = options || {};
 
   var compiled;

spec/qunit_spec.js

@@ -1245,3 +1245,9 @@ test("bug reported by @fat where lambdas weren't being properly resolved", funct
   var output = "<strong>This is a slightly more complicated blah.</strong>.\n\nCheck this out:\n\n<ul>\n\n<li class=one>@fat</li>\n\n<li class=two>@dhg</li>\n\n<li class=three>@sayrer</li>\n</ul>.\n\n";
   shouldCompileTo(string, data, output);
 });
+
+test("Passing falsy values to Handlebars.compile throws an error", function() {
+  shouldThrow(function() {
+    CompilerContext.compile(null);
+  }, "You must pass a string to Handlebars.compile. You passed null");
+});