diff --git a/spec/text-buffer-spec.js b/spec/text-buffer-spec.js
new file mode 100644
index 0000000000..113a3bc2a1
--- /dev/null
+++ b/spec/text-buffer-spec.js
@@ -0,0 +1,14 @@
+const path = require('path')
+const TextBuffer = require('../src/text-buffer')
+
+describe('when a buffer is already open', () => {
+  it('replaces foo( with bar( using /\bfoo\\(\b/gim', () => {
+    const filePath = path.join(__dirname, 'fixtures', 'sample.js')
+    const buffer = new TextBuffer()
+    buffer.setPath(filePath)
+    buffer.setText('foo(x)')
+    buffer.replace(/\bfoo\(\b/gim, 'bar(')
+
+    expect(buffer.getText()).toBe('bar(x)')
+  })
+})
diff --git a/src/text-buffer.js b/src/text-buffer.js
index df1f4775fb..73c7ffbd8b 100644
--- a/src/text-buffer.js
+++ b/src/text-buffer.js
@@ -1608,8 +1608,8 @@ class TextBuffer {
     let replacements = 0
 
     this.transact(() => {
-      return this.scan(regex, function ({matchText, replace}) {
-        replace(matchText.replace(regex, replacementText))
+      return this.scan(regex, function ({replace}) {
+        replace(replacementText)
         return replacements++
       })
     })