Add tests and longer error explanation

1 files changed, 24 insertions, 1 deletions

diff --git a/src/libsyntax_ext/diagnostics.rs b/src/libsyntax_ext/diagnostics.rs
index e247a22aeb0..a840c0392e9 100644
--- a/src/libsyntax_ext/diagnostics.rs
+++ b/src/libsyntax_ext/diagnostics.rs
@@ -1,4 +1,4 @@
-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -15,8 +15,31 @@
 // In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use `:set tw=0` to disable.
 register_long_diagnostics! {
 E0660: r##"
+The argument to the `asm` macro is not well-formed.
+
+Erroneous code example:
+
+```compile_fail,E0660
+asm!("nop" "nop");
+```
+
+Considering that this would be a long explanation, we instead recommend you to
+take a look at the unstable book:
+https://doc.rust-lang.org/unstable-book/language-features/asm.html
 "##,
 
 E0661: r##"
+An invalid syntax was passed to the second argument of an `asm` macro line.
+
+Erroneous code example:
+
+```compile_fail,E0661
+let a;
+asm!("nop" : "r"(a));
+```
+
+Considering that this would be a long explanation, we instead recommend you to
+take a look at the unstable book:
+https://doc.rust-lang.org/unstable-book/language-features/asm.html
 "##,
 }