From c8fa225cb4241d68c51a43f311720d73af0eb390 Mon Sep 17 00:00:00 2001
From: Justin Ridgewell <justin@ridgewell.name>
Date: Thu, 16 Sep 2021 16:16:10 -0400
Subject: [PATCH] Fix inlining object spread properties (#1071)

---
 lib/compress/index.js       |  2 ++
 test/compress/expansions.js | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/lib/compress/index.js b/lib/compress/index.js
index 4c393151b..7c62c8235 100644
--- a/lib/compress/index.js
+++ b/lib/compress/index.js
@@ -4335,9 +4335,11 @@ function inline_object_prop_spread(props, compressor) {
                 // non-iterable value silently does nothing; it is thus safe
                 // to remove. AST_String is the only iterable AST_Constant.
                 props.splice(i, 1);
+                i--;
             } else if (is_nullish(expr, compressor)) {
                 // Likewise, null and undefined can be silently removed.
                 props.splice(i, 1);
+                i--;
             }
         }
     }
diff --git a/test/compress/expansions.js b/test/compress/expansions.js
index ca651efdc..af90f0935 100644
--- a/test/compress/expansions.js
+++ b/test/compress/expansions.js
@@ -103,6 +103,31 @@ object_spread: {
     ]
 }
 
+object_spread_nullish_undefined: {
+    input: {
+        let o = { ...undefined, ...{a: true} }
+        id(o);
+    }
+
+    expect: {
+        let o = {a: true};
+        id(o)
+    }
+}
+
+object_spread_nullish_null: {
+    input: {
+        let o = { ...null, ...{a: true} }
+        id(o);
+    }
+
+    expect: {
+        let o = {a: true};
+        id(o)
+    }
+}
+
+
 avoid_spread_hole: {
     input: {
         let x = [...[,]]