Add `rustc_fluent_macro` to decouple fluent from `rustc_macros`

Fluent, with all the icu4x it brings in, takes quite some time to
compile. `fluent_messages!` is only needed in further downstream rustc
crates, but is blocking more upstream crates like `rustc_index`. By
splitting it out, we allow `rustc_macros` to be compiled earlier, which
speeds up `x check compiler` by about 5 seconds (and even more after the
needless dependency on `serde_json` is removed from
`rustc_data_structures`).

2 files changed, 2 insertions, 1 deletions

diff --git a/compiler/rustc_errors/Cargo.toml b/compiler/rustc_errors/Cargo.toml
index e1ead08ea66..46ace8eb2dd 100644
--- a/compiler/rustc_errors/Cargo.toml
+++ b/compiler/rustc_errors/Cargo.toml
@@ -10,6 +10,7 @@ tracing = "0.1"
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
 rustc_error_messages = { path = "../rustc_error_messages" }
+rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
 rustc_macros = { path = "../rustc_macros" }
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index d20b168904d..bdf58241807 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -38,8 +38,8 @@ pub use rustc_error_messages::{
     fallback_fluent_bundle, fluent_bundle, DelayDm, DiagnosticMessage, FluentBundle,
     LanguageIdentifier, LazyFallbackBundle, MultiSpan, SpanLabel, SubdiagnosticMessage,
 };
+use rustc_fluent_macro::fluent_messages;
 pub use rustc_lint_defs::{pluralize, Applicability};
-use rustc_macros::fluent_messages;
 use rustc_span::source_map::SourceMap;
 pub use rustc_span::ErrorGuaranteed;
 use rustc_span::{Loc, Span};