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+Multiple types were used as bounds for a closure or trait object.
+
+Erroneous code example:
+
+```compile_fail,E0225
+fn main() {
+    let _: Box<dyn std::io::Read + std::io::Write>;
+}
+```
+
+Rust does not currently support this.
+
+Auto traits such as Send and Sync are an exception to this rule:
+It's possible to have bounds of one non-builtin trait, plus any number of
+auto traits. For example, the following compiles correctly:
+
+```
+fn main() {
+    let _: Box<dyn std::io::Read + Send + Sync>;
+}
+```