diff --git a/src/doc/trpl/README.md b/src/doc/trpl/README.md
index b2e1a6ec0bc..8d3a6ec3986 100644
--- a/src/doc/trpl/README.md
+++ b/src/doc/trpl/README.md
@@ -116,7 +116,7 @@ fn main() {
 
     let y = &x[0];
 
-    x.push(4);
+    x.push("foo");
 }
 ```
 
@@ -159,7 +159,7 @@ fn main() {
 
     let y = x[0].clone();
 
-    x.push(4);
+    x.push("foo");
 }
 ```
 
@@ -181,7 +181,7 @@ fn main() {
         let y = &x[0];
     }
 
-    x.push(4);
+    x.push("foo");
 }
 ```