Temporarily make allow-by-default the non_local_definitions lint

compiler/rustc_lint/src/non_local_def.rs

@@ -14,6 +14,7 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
+    /// #![warn(non_local_definitions)]
     /// trait MyTrait {}
     /// struct MyStruct;
     ///
@@ -36,7 +37,7 @@ declare_lint! {
     /// All nested bodies (functions, enum discriminant, array length, consts) (expect for
     /// `const _: Ty = { ... }` in top-level module, which is still undecided) are checked.
     pub NON_LOCAL_DEFINITIONS,
-    Warn,
+    Allow,
     "checks for non-local definitions",
     report_in_external_macro
 }

tests/ui/lint/non_local_definitions.rs

@@ -4,6 +4,7 @@
 //@ rustc-env:CARGO=/usr/bin/cargo
 
 #![feature(inline_const)]
+#![warn(non_local_definitions)]
 
 extern crate non_local_macro;