fix: allow member access on directives

packages/svelte/src/compiler/phases/1-parse/state/element.js

@@ -467,7 +467,16 @@ function read_attribute(parser, unique_names) {
 	}
 
 	if (type) {
-		const [directive_name, ...modifiers] = name.slice(colon_index + 1).split('|');
+		const [base_directive_name, ...modifiers] = name.slice(colon_index + 1).split('|');
+
+		// this allow for accessing members of an object
+		const splitted_directive = base_directive_name.split('.');
+
+		let directive_name = splitted_directive.shift() ?? '';
+
+		for (let new_piece of splitted_directive) {
+			directive_name += `['${new_piece}']`;
+		}
 
 		if (directive_name === '') {
 			error(start + colon_index + 1, 'empty-directive-name', type);

packages/svelte/tests/parser-legacy/samples/action-with-memberaccess/input.svelte

@@ -0,0 +1 @@
+<input use:nested.action>

packages/svelte/tests/parser-legacy/samples/action-with-memberaccess/output.json

@@ -0,0 +1,26 @@
+{
+	"html": {
+		"type": "Fragment",
+		"start": 0,
+		"end": 25,
+		"children": [
+			{
+				"type": "Element",
+				"start": 0,
+				"end": 25,
+				"name": "input",
+				"attributes": [
+					{
+						"start": 7,
+						"end": 24,
+						"type": "Action",
+						"name": "nested['action']",
+						"modifiers": [],
+						"expression": null
+					}
+				],
+				"children": []
+			}
+		]
+	}
+}