Also mark nested functions as pure

src/ast/nodes/Identifier.ts

@@ -293,6 +293,9 @@ export default class Identifier extends NodeBase implements PatternNode {
 		let currentPureFunction = this.context.manualPureFunctions[this.name];
 		for (const segment of path) {
 			if (currentPureFunction) {
+				if (currentPureFunction[PureFunctionKey]) {
+					return true;
+				}
 				currentPureFunction = currentPureFunction[segment as string];
 			} else {
 				return false;

test/form/samples/manual-pure-functions/_config.js

@@ -1,6 +1,9 @@
 module.exports = {
+	solo: true,
 	description: 'allows to manually declare functions as pure by name',
 	options: {
-		treeshake: { manualPureFunctions: ['foo', 'bar.baz'] }
+		treeshake: { manualPureFunctions: ['foo', 'bar.a'] }
 	}
 };
+// TODO Lukas also tagged templates
+// TODO Lukas also check "this" or arguments are not deoptimized

test/form/samples/manual-pure-functions/_expected.js

@@ -1,5 +1,11 @@
 const lib = () => console.log();
-lib.baz = console.log;
+lib.a = () => {
+	console.log();
+	const result = () => console.log();
+	result.c = console.log;
+	return result;
+};
+lib.a.b = () => console.log();
 
 lib(); // not removed
-lib.quuz(); // not removed
+lib.b(); // not removed

test/form/samples/manual-pure-functions/main.js

@@ -2,7 +2,10 @@ import { lib as bar } from './other';
 const foo = console.log;
 
 foo(); // removed
-bar.baz(); // removed
+bar.a(); // removed
+bar?.a(); // removed
+
 bar(); // not removed
-bar.quuz(); // not removed
-bar?.baz(); // removed
+bar.b(); // not removed
+
+bar.a.b(); // removed

test/form/samples/manual-pure-functions/other.js

@@ -1,2 +1,8 @@
 export const lib = () => console.log();
-lib.baz = console.log;
+lib.a = () => {
+	console.log();
+	const result = () => console.log();
+	result.c = console.log;
+	return result;
+};
+lib.a.b = () => console.log();