[embind] Fix type in overloadTable error checking. NFC

Author: sbc100

src/embind/embind.js

@@ -124,7 +124,7 @@ var LibraryEmbind = {
       // We are exposing a function with the same name as an existing function. Create an overload table and a function selector
       // that routes between the two.
       ensureOverloadTable(Module, name, name);
-      if (Module.hasOwnProperty(numArguments)) {
+      if (Module[name].overloadTable.hasOwnProperty(numArguments)) {
         throwBindingError(`Cannot register multiple overloads of a function with the same number of arguments (${numArguments})!`);
       }
       // Add the new function into the overload table.

test/code_size/embind_hello_wasm.json

@@ -1,10 +1,10 @@
 {
   "a.html": 552,
   "a.html.gz": 380,
-  "a.js": 9727,
-  "a.js.gz": 4295,
+  "a.js": 9732,
+  "a.js.gz": 4296,
   "a.wasm": 7730,
   "a.wasm.gz": 3507,
-  "total": 18009,
-  "total_gz": 8182
+  "total": 18014,
+  "total_gz": 8183
 }

test/embind/test_embind_invalid_overload.cpp

@@ -0,0 +1,22 @@
+#include <functional>
+#include <emscripten/bind.h>
+
+using namespace emscripten;
+
+int main() {
+}
+
+int foo(int a) {
+  return 0;
+}
+
+int foo(float a) {
+  return 0;
+}
+
+EMSCRIPTEN_BINDINGS(bindings) {
+  // Overloads in embind all need to have a unique number of arguments.
+  // This is invalid since both overloads take just one argument.
+  function("foo", select_overload<int(int)>(&foo));
+  function("foo", select_overload<int(float)>(&foo));
+}

test/test_other.py

@@ -3127,6 +3127,10 @@ def test_embind_fail(self):
     out = self.expect_fail([EMXX, test_file('embind/test_unsigned.cpp')])
     self.assertContained("undefined symbol: _embind_register_function", out)
 
+  def test_embind_invalid_overload(self):
+    err = self.expect_fail([EMCC, test_file('embind/test_embind_invalid_overload.cpp'), '-lembind', '-c'])
+    self.assertContained('BindingError: Cannot register multiple overloads of a function with the same number of arguments (1)!', err)
+
   def test_embind_asyncify(self):
     create_file('post.js', '''
       addOnPostRun(() => {