From 451612141d62539d008757535ba1a29400e2d959 Mon Sep 17 00:00:00 2001
From: Nguyen Tran <nguyen.tran1072e@gmail.com>
Date: Sat, 25 Mar 2023 17:47:16 -0400
Subject: [PATCH] Fix issue where we can't find previous sibling because of
 nested slots

---
 src/compiler/compile/css/Selector.ts                      | 8 ++++----
 .../expected.css                                          | 1 +
 .../input.svelte                                          | 7 +++++++
 .../expected.css                                          | 1 +
 .../input.svelte                                          | 7 +++++++
 5 files changed, 20 insertions(+), 4 deletions(-)
 create mode 100644 test/css/samples/general-siblings-combinator-nested-slots-flattened/expected.css
 create mode 100644 test/css/samples/general-siblings-combinator-nested-slots-flattened/input.svelte
 create mode 100644 test/css/samples/siblings-combinator-nested-slots-flattened/expected.css
 create mode 100644 test/css/samples/siblings-combinator-nested-slots-flattened/input.svelte

diff --git a/src/compiler/compile/css/Selector.ts b/src/compiler/compile/css/Selector.ts
index f2839ba36a..19fac1f314 100644
--- a/src/compiler/compile/css/Selector.ts
+++ b/src/compiler/compile/css/Selector.ts
@@ -483,11 +483,11 @@ function find_previous_sibling_ignoring_slots(node: INode): INode {
 		}
 
 		// @ts-ignore
-		if (!current_node.prev && current_node.parent.type === 'Slot') {
-			current_node = current_node.parent.prev;
-		} else {
-			current_node = current_node.prev;
+		while (!current_node.prev && current_node.parent && current_node.parent.type === 'Slot') {
+			current_node = current_node.parent;
 		}
+		current_node = current_node.prev;
+
 	// @ts-ignore
 	} while (current_node && current_node.type === 'Slot');
 
diff --git a/test/css/samples/general-siblings-combinator-nested-slots-flattened/expected.css b/test/css/samples/general-siblings-combinator-nested-slots-flattened/expected.css
new file mode 100644
index 0000000000..f365e3dc24
--- /dev/null
+++ b/test/css/samples/general-siblings-combinator-nested-slots-flattened/expected.css
@@ -0,0 +1 @@
+h1.svelte-xyz~p.svelte-xyz{color:red}
\ No newline at end of file
diff --git a/test/css/samples/general-siblings-combinator-nested-slots-flattened/input.svelte b/test/css/samples/general-siblings-combinator-nested-slots-flattened/input.svelte
new file mode 100644
index 0000000000..0d521b8385
--- /dev/null
+++ b/test/css/samples/general-siblings-combinator-nested-slots-flattened/input.svelte
@@ -0,0 +1,7 @@
+<slot><slot><h1>Heading 1</h1></slot></slot><span>Span 1</span><span>Span 2</span><slot><slot><p>Paragraph 2</p></slot></slot>
+
+<style>
+  h1 ~ p {
+    color: red;
+  }
+</style>
diff --git a/test/css/samples/siblings-combinator-nested-slots-flattened/expected.css b/test/css/samples/siblings-combinator-nested-slots-flattened/expected.css
new file mode 100644
index 0000000000..d523f1d533
--- /dev/null
+++ b/test/css/samples/siblings-combinator-nested-slots-flattened/expected.css
@@ -0,0 +1 @@
+h1.svelte-xyz+span.svelte-xyz{color:red}
\ No newline at end of file
diff --git a/test/css/samples/siblings-combinator-nested-slots-flattened/input.svelte b/test/css/samples/siblings-combinator-nested-slots-flattened/input.svelte
new file mode 100644
index 0000000000..475aa85426
--- /dev/null
+++ b/test/css/samples/siblings-combinator-nested-slots-flattened/input.svelte
@@ -0,0 +1,7 @@
+<slot><slot><slot><h1>test</h1></slot></slot></slot><slot><slot><span>Hello</span></slot></slot>
+
+<style>
+  h1 + span {
+    color: red;
+  }
+</style>