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+An associated type whose name does not match any of the associated types
+in the trait was used when implementing the trait.
+
+Erroneous code example:
+
+```compile_fail,E0437
+trait Foo {}
+
+impl Foo for i32 {
+    type Bar = bool;
+}
+```
+
+Trait implementations can only implement associated types that are members of
+the trait in question.
+
+The solution to this problem is to remove the extraneous associated type:
+
+```
+trait Foo {}
+
+impl Foo for i32 {}
+```