fix style scoping with > * (#5400)

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Fix scoping of styles involving child selector and `*` ([#5370](https://github.com/sveltejs/svelte/issues/5370))
+
 ## 3.25.0
 
 * Use `null` rather than `undefined` for coerced bound value of `<input type="number">` ([#1701](https://github.com/sveltejs/svelte/issues/1701))

src/compiler/compile/css/Selector.ts

@@ -152,7 +152,7 @@ function apply_selector(blocks: Block[], node: Element, stack: Element[], to_enc
 	if (!block) return false;
 
 	if (!node) {
-		return blocks.every(block => block.global);
+		return block.global && blocks.every(block => block.global);
 	}
 
 	switch (block_might_apply_to_node(block, node)) {
@@ -208,7 +208,7 @@ function apply_selector(blocks: Block[], node: Element, stack: Element[], to_enc
 	return true;
 }
 
-function block_might_apply_to_node(block, node): BlockAppliesToNode {
+function block_might_apply_to_node(block: Block, node: Element): BlockAppliesToNode {
 	let i = block.selectors.length;
 
 	while (i--) {

test/css/samples/unused-selector-child-combinator/_config.js

@@ -0,0 +1,45 @@
+export default {
+	warnings: [
+		{
+			code: "css-unused-selector",
+			message: 'Unused CSS selector "article > *"',
+			frame: `
+			1: <style>
+			2:   article > * {
+			     ^
+			3:     font-size: 36px;
+			4:   }`,
+			pos: 10,
+			start: { character: 10, column: 1, line: 2 },
+			end: { character: 21, column: 12, line: 2 }
+		},
+		{
+			code: "css-unused-selector",
+			message: 'Unused CSS selector "article *"',
+			frame: `
+			4:   }
+			5:
+			6:   article * {
+			     ^
+			7:     font-size: 36px;
+			8:   }`,
+			pos: 49,
+			start: { character: 49, column: 1, line: 6 },
+			end: { character: 58, column: 10, line: 6 }
+		},
+		{
+			code: "css-unused-selector",
+			message: 'Unused CSS selector ".article > *"',
+			frame: `
+			 8:   }
+			 9:
+			10:   .article > * {
+			      ^
+			11:     font-size: 48px;
+			12:   }`,
+			pos: 86,
+			start: { character: 86, column: 1, line: 10 },
+			end: { character: 98, column: 13, line: 10 }
+		}
+	]
+};

test/css/samples/unused-selector-child-combinator/expected.css

@@ -0,0 +1 @@
+div.svelte-xyz>.svelte-xyz{color:orange}

test/css/samples/unused-selector-child-combinator/input.svelte

@@ -0,0 +1,23 @@
+<style>	
+	article > * {
+		font-size: 36px;
+  }
+
+	article * {
+		font-size: 36px;
+	}
+	
+	.article > * {
+		font-size: 48px;
+	}
+	
+	div > * {
+		color: orange;
+	}
+</style>
+
+<div>
+	<p>
+		Svelte REPLs are svelte.
+	</p>
+</div>