From e8a4b9319cbf5b3f56b3cdd8ad11e86ff7168345 Mon Sep 17 00:00:00 2001 From: Guillaume Gomez Date: Fri, 17 Jan 2020 19:54:07 +0100 Subject: [PATCH] Clean up E0199 explanation --- src/librustc_error_codes/error_codes/E0199.md | 21 +++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/src/librustc_error_codes/error_codes/E0199.md b/src/librustc_error_codes/error_codes/E0199.md index d0c12dc6f1755..88130e8e5e596 100644 --- a/src/librustc_error_codes/error_codes/E0199.md +++ b/src/librustc_error_codes/error_codes/E0199.md @@ -1,14 +1,23 @@ +A trait implementation was marked as unsafe while the trait is safe. + +Erroneous code example: + +```compile_fail,E0199 +struct Foo; + +trait Bar { } + +unsafe impl Bar for Foo { } // error! +``` + Safe traits should not have unsafe implementations, therefore marking an implementation for a safe trait unsafe will cause a compiler error. Removing -the unsafe marker on the trait noted in the error will resolve this problem. +the unsafe marker on the trait noted in the error will resolve this problem: -```compile_fail,E0199 +``` struct Foo; trait Bar { } -// this won't compile because Bar is safe -unsafe impl Bar for Foo { } -// this will compile -impl Bar for Foo { } +impl Bar for Foo { } // ok! ```