From 3ac6d717e3f4f11a16b91013f8c43531a95f641d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Fri, 25 Feb 2022 20:04:28 +0100
Subject: [PATCH 1/2] Disallow `<` after a JSX  element

---
 spec.emu | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/spec.emu b/spec.emu
index 1692fb8..4e85184 100644
--- a/spec.emu
+++ b/spec.emu
@@ -52,10 +52,30 @@ render(dropdown);
 
     <h2>Syntax</h2>
     <emu-grammar>
-      PrimaryExpression :
-        <ins>JSXElement</ins>
-        <ins>JSXFragment</ins>
+      PrimaryExpression ::
+        <ins>JSXElementOrFragment `<`</ins>
+        <ins>JSXElementOrFragment</ins>
     </emu-grammar>
+
+    <emu-clause type="sdo" id="sec-jsx-PrimaryExpression-early-errors">
+      <h1>Static Semantics: Early Errors</h1>
+      <emu-grammar>
+        PrimaryExpression :: JSXElementOrFragment `<`
+      </emu-grammar>
+      <ul>
+        <li>It is a SyntaxError if any source text is matched by this production.</li>
+      </ul>
+      <emu-note>
+        This Early Error prevents users from accidentally writing two adjacent JSX elements without wrapping them in a fragment:
+          <pre><code class="language-jsx">
+// Invalid
+var elts = &lt;a&gt;&lt;/a&gt;&lt;b&gt;&lt;/b&gt;
+
+// Valid
+var elts = &lt;&gt;&lt;a&gt;&lt;/a&gt;&lt;b&gt;&lt;/b&gt;&lt;/&gt;
+  </code></pre>
+      </emu-note>
+    </emu-clause>
   </emu-clause>
 
   <emu-clause id="sec-jsx-elements">
@@ -63,6 +83,10 @@ render(dropdown);
     <h2>Syntax</h2>
 
     <emu-grammar type="definition">
+      JSXElementOrFragment ::
+        JSXElement
+        JSXFragment
+
       JSXElement :
         JSXSelfClosingElement
         JSXOpeningElement JSXChildren? JSXClosingElement

From 58edf8d8401b45ce50c4a7f9de7a2cf609f059e9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Sat, 5 Mar 2022 12:14:02 +0100
Subject: [PATCH 2/2] Update spec.emu
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Xuan Huang (黄玄) <huxpro@gmail.com>
---
 spec.emu | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spec.emu b/spec.emu
index 4e85184..2b31aae 100644
--- a/spec.emu
+++ b/spec.emu
@@ -52,7 +52,7 @@ render(dropdown);
 
     <h2>Syntax</h2>
     <emu-grammar>
-      PrimaryExpression ::
+      PrimaryExpression :
         <ins>JSXElementOrFragment `<`</ins>
         <ins>JSXElementOrFragment</ins>
     </emu-grammar>