From d46d67f1c71d3ad143d3d03a0f681c7f8885d308 Mon Sep 17 00:00:00 2001
From: Rich-Harris <richard.a.harris@gmail.com>
Date: Tue, 2 Jun 2015 14:55:30 -0400
Subject: [PATCH] method call is assumed to mutate method owner (#13)

---
 src/Statement.js                                  |  5 +++++
 test/function/method-call-mutates-this/_config.js |  3 +++
 test/function/method-call-mutates-this/foo.js     | 15 +++++++++++++++
 test/function/method-call-mutates-this/main.js    |  3 +++
 4 files changed, 26 insertions(+)
 create mode 100644 test/function/method-call-mutates-this/_config.js
 create mode 100644 test/function/method-call-mutates-this/foo.js
 create mode 100644 test/function/method-call-mutates-this/main.js

diff --git a/src/Statement.js b/src/Statement.js
index 1c46cc0..fdc0cab 100644
--- a/src/Statement.js
+++ b/src/Statement.js
@@ -188,6 +188,11 @@ export default class Statement {
 
 		else if ( node.type === 'CallExpression' ) {
 			node.arguments.forEach( arg => addNode( arg, false ) );
+
+			// `foo.bar()` is assumed to mutate foo
+			if ( node.callee.type === 'MemberExpression' ) {
+				addNode( node.callee );
+			}
 		}
 	}
 
diff --git a/test/function/method-call-mutates-this/_config.js b/test/function/method-call-mutates-this/_config.js
new file mode 100644
index 0000000..66fe25b
--- /dev/null
+++ b/test/function/method-call-mutates-this/_config.js
@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'method calls are assumed to mutate the owner'
+};
diff --git a/test/function/method-call-mutates-this/foo.js b/test/function/method-call-mutates-this/foo.js
new file mode 100644
index 0000000..b58506d
--- /dev/null
+++ b/test/function/method-call-mutates-this/foo.js
@@ -0,0 +1,15 @@
+var obj = {
+	set: function ( key, value ) {
+		this[ key ] = value;
+	},
+
+	get: function ( key ) {
+		return this[ key ];
+	}
+};
+
+obj.set( 'answer', 42 );
+
+export default function ( key ) {
+	return obj.get( key );
+}
diff --git a/test/function/method-call-mutates-this/main.js b/test/function/method-call-mutates-this/main.js
new file mode 100644
index 0000000..354a618
--- /dev/null
+++ b/test/function/method-call-mutates-this/main.js
@@ -0,0 +1,3 @@
+import foo from './foo';
+
+assert.equal( foo( 'answer' ), 42 );