From 4d5fe5dea6ab3264ed5d49b5baccd13b8fe38ca0 Mon Sep 17 00:00:00 2001
From: Alexandre Galays <boubiyeah@hotmail.com>
Date: Thu, 28 Jan 2021 12:56:40 +0100
Subject: [PATCH 1/4] Swap the order of the two derived store signatures to fix
 inference (#5935)

---
 src/runtime/store/index.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/runtime/store/index.ts b/src/runtime/store/index.ts
index 09040487f0..c8e2b4ff99 100644
--- a/src/runtime/store/index.ts
+++ b/src/runtime/store/index.ts
@@ -125,10 +125,12 @@ type StoresValues<T> = T extends Readable<infer U> ? U :
  *
  * @param stores - input stores
  * @param fn - function callback that aggregates the values
+ * @param initial_value - when used asynchronously
  */
 export function derived<S extends Stores, T>(
 	stores: S,
-	fn: (values: StoresValues<S>) => T
+	fn: (values: StoresValues<S>, set: (value: T) => void) => Unsubscriber | void,
+	initial_value?: T
 ): Readable<T>;
 
 /**
@@ -137,12 +139,10 @@ export function derived<S extends Stores, T>(
  *
  * @param stores - input stores
  * @param fn - function callback that aggregates the values
- * @param initial_value - when used asynchronously
  */
 export function derived<S extends Stores, T>(
 	stores: S,
-	fn: (values: StoresValues<S>, set: (value: T) => void) => Unsubscriber | void,
-	initial_value?: T
+	fn: (values: StoresValues<S>) => T
 ): Readable<T>;
 
 export function derived<T>(stores: Stores, fn: Function, initial_value?: T): Readable<T> {

From b3431f9bf204cee58db751e083f3e45198379cb8 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Fri, 29 Jan 2021 10:20:06 -0500
Subject: [PATCH 2/4] update changelog

---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 18387d2090..c8e3a1d181 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Fix type inference for derived stores ([#5935](https://github.com/sveltejs/svelte/pull/5935))
+
 ## 3.32.0
 
 * Allow multiple instances of the same action on an element ([#5516](https://github.com/sveltejs/svelte/issues/5516))

From acf60d88a069ee3df2eafd122106db3acc560bd0 Mon Sep 17 00:00:00 2001
From: Anders Lorentsen <Phaqui@gmail.com>
Date: Fri, 29 Jan 2021 16:33:40 +0100
Subject: [PATCH 3/4] error on empty name in `class:` directive (#5939)

---
 src/compiler/parse/state/tag.ts                        |  7 +++++++
 .../samples/error-empty-classname-binding/error.json   | 10 ++++++++++
 .../samples/error-empty-classname-binding/input.svelte |  1 +
 3 files changed, 18 insertions(+)
 create mode 100644 test/parser/samples/error-empty-classname-binding/error.json
 create mode 100644 test/parser/samples/error-empty-classname-binding/input.svelte

diff --git a/src/compiler/parse/state/tag.ts b/src/compiler/parse/state/tag.ts
index 696a47b649..aedffffe21 100644
--- a/src/compiler/parse/state/tag.ts
+++ b/src/compiler/parse/state/tag.ts
@@ -387,6 +387,13 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 			}, start);
 		}
 
+		if (type === 'Class' && directive_name === '') {
+			parser.error({
+				code: 'invalid-class-directive',
+				message: 'Class binding name cannot be empty'
+			}, start + colon_index + 1);
+		}
+
 		if (value[0]) {
 			if ((value as any[]).length > 1 || value[0].type === 'Text') {
 				parser.error({
diff --git a/test/parser/samples/error-empty-classname-binding/error.json b/test/parser/samples/error-empty-classname-binding/error.json
new file mode 100644
index 0000000000..edc09ff8e1
--- /dev/null
+++ b/test/parser/samples/error-empty-classname-binding/error.json
@@ -0,0 +1,10 @@
+{
+	"code": "invalid-class-directive",
+	"message": "Class binding name cannot be empty",
+	"start": {
+		"line": 1,
+		"column": 10,
+		"character": 10
+	},
+	"pos": 10
+}
diff --git a/test/parser/samples/error-empty-classname-binding/input.svelte b/test/parser/samples/error-empty-classname-binding/input.svelte
new file mode 100644
index 0000000000..3a4e5980ee
--- /dev/null
+++ b/test/parser/samples/error-empty-classname-binding/input.svelte
@@ -0,0 +1 @@
+<h1 class:={true}>Hello</h1>

From f00348c14c430e23ff48ec4f3c0580fa2cf0c9a0 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Fri, 29 Jan 2021 10:34:30 -0500
Subject: [PATCH 4/4] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c8e3a1d181..928f76bfc9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Throw a parser error for `class:` directives with an empty class name ([#5858](https://github.com/sveltejs/svelte/issues/5858))
 * Fix type inference for derived stores ([#5935](https://github.com/sveltejs/svelte/pull/5935))
 
 ## 3.32.0