From aa661cf6cdc4e745f00799a6167fb15ae02e2f73 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <lhtan93@gmail.com>
Date: Thu, 18 Jun 2020 21:28:31 +0800
Subject: [PATCH 1/2] fix extract names from ThisExpression

---
 src/compiler/compile/nodes/shared/Expression.ts        |  7 ++-----
 .../samples/this-in-function-expressions/_config.js    | 10 ++++++++++
 .../samples/this-in-function-expressions/main.svelte   |  2 ++
 3 files changed, 14 insertions(+), 5 deletions(-)
 create mode 100644 test/runtime/samples/this-in-function-expressions/_config.js
 create mode 100644 test/runtime/samples/this-in-function-expressions/main.svelte

diff --git a/src/compiler/compile/nodes/shared/Expression.ts b/src/compiler/compile/nodes/shared/Expression.ts
index f7c9897d586c..c7c66940fddb 100644
--- a/src/compiler/compile/nodes/shared/Expression.ts
+++ b/src/compiler/compile/nodes/shared/Expression.ts
@@ -120,12 +120,9 @@ export default class Expression {
 				if (function_expression) {
 					if (node.type === 'AssignmentExpression') {
 						deep = node.left.type === 'MemberExpression';
-						names = deep
-							? [get_object(node.left).name]
-							: extract_names(node.left);
+						names = extract_names(deep ? get_object(node.left) : node.left);
 					} else if (node.type === 'UpdateExpression') {
-						const { name } = get_object(node.argument);
-						names = [name];
+						names = extract_names(get_object(node.argument));
 					}
 				}
 
diff --git a/test/runtime/samples/this-in-function-expressions/_config.js b/test/runtime/samples/this-in-function-expressions/_config.js
new file mode 100644
index 000000000000..4110d05a48a0
--- /dev/null
+++ b/test/runtime/samples/this-in-function-expressions/_config.js
@@ -0,0 +1,10 @@
+export default {
+	async test({ assert, component, target, window, raf }) {
+		const [_, btn] = target.querySelectorAll("button");
+		const clickEvent = new window.MouseEvent("click");
+
+		await btn.dispatchEvent(clickEvent);
+
+		assert.equal(btn.x, 1);
+	},
+};
diff --git a/test/runtime/samples/this-in-function-expressions/main.svelte b/test/runtime/samples/this-in-function-expressions/main.svelte
new file mode 100644
index 000000000000..af732920e9e3
--- /dev/null
+++ b/test/runtime/samples/this-in-function-expressions/main.svelte
@@ -0,0 +1,2 @@
+<button on:click="{() => { this.x = 1; }}" />
+<button on:click="{function () { this.x = 1; }}" />

From 6174a7d1e1ae715d67d653aad4f6ed531c89abb7 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 23 Jun 2020 10:00:16 -0400
Subject: [PATCH 2/2] update changelog

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

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dfa08fdf4222..6757221f4806 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Fix handling of `this` in inline function expressions in the template ([#5033](https://github.com/sveltejs/svelte/issues/5033))
+
 ## 3.23.2
 
 * Fix `bind:group` inside `{#each}` ([#3243](https://github.com/sveltejs/svelte/issues/3243))