Fix counting of nested self-closing JSXOpeningElements

* lisp/progmodes/js.el (js-jsx--matching-close-tag-pos): Fix bug where
self-closing JSXOpeningElements might be missed if one was nested
within another.

* test/manual/indent/jsx-self-closing.jsx: Add test for bug concerning
self-closing JSXOpeningElement counting.

1 files changed, 13 insertions, 0 deletions

diff --git a/test/manual/indent/jsx-self-closing.jsx b/test/manual/indent/jsx-self-closing.jsx
new file mode 100644
index 00000000000..f8ea7a138ad
--- /dev/null
+++ b/test/manual/indent/jsx-self-closing.jsx
@@ -0,0 +1,13 @@
+// Local Variables:
+// indent-tabs-mode: nil
+// js-indent-level: 2
+// End:
+
+// The following test goes below any comments to avoid including
+// misindented comments among the erroring lines.
+
+// Properly parse/indent code with a self-closing tag inside the
+// attribute of another self-closing tag.
+<div>
+  <div attr={() => <div attr="" />} />
+</div>