Preserve escape sequences in documentation comments on macro expansion

Escape sequences in documentation comments must not be parsed as a
normal string when expanding a macro, otherwise some innocent but
invalid-escape-sequence-looking comments will trigger an ICE.

Although this commit replaces normal string literals with raw string
literals in macro expansion, this shouldn't be much a problem
considering documentation comments are converted into attributes before
being passed to a macro anyways.

Fixes #25929.
Fixes #25943.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index e844b206cc0..a944acad84d 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1104,7 +1104,7 @@ impl TokenTree {
                     tts: vec![TtToken(sp, token::Ident(token::str_to_ident("doc"),
                                                        token::Plain)),
                               TtToken(sp, token::Eq),
-                              TtToken(sp, token::Literal(token::Str_(name), None))],
+                              TtToken(sp, token::Literal(token::StrRaw(name, 0), None))],
                     close_span: sp,
                 }))
             }