Factor out common token generation in `fluent_messages`.

The failure and success cases are similar enough that they can share
code.

1 files changed, 20 insertions, 38 deletions

diff --git a/compiler/rustc_fluent_macro/src/fluent.rs b/compiler/rustc_fluent_macro/src/fluent.rs
index 56e23ac2775..7479e4ef2b3 100644
--- a/compiler/rustc_fluent_macro/src/fluent.rs
+++ b/compiler/rustc_fluent_macro/src/fluent.rs
@@ -40,26 +40,35 @@ fn invocation_relative_path_to_absolute(span: Span, path: &str) -> PathBuf {
     }
 }
 
-/// Tokens to be returned when the macro cannot proceed.
-fn failed(crate_name: &Ident) -> proc_macro::TokenStream {
+/// Final tokens.
+fn finish(body: TokenStream, resource: TokenStream) -> proc_macro::TokenStream {
     quote! {
-        pub static DEFAULT_LOCALE_RESOURCE: &'static str = "";
+        /// Raw content of Fluent resource for this crate, generated by `fluent_messages` macro,
+        /// imported by `rustc_driver` to include all crates' resources in one bundle.
+        pub static DEFAULT_LOCALE_RESOURCE: &'static str = #resource;
 
         #[allow(non_upper_case_globals)]
         #[doc(hidden)]
+        /// Auto-generated constants for type-checked references to Fluent messages.
         pub(crate) mod fluent_generated {
-            pub mod #crate_name {
-            }
+            #body
 
+            /// Constants expected to exist by the diagnostic derive macros to use as default Fluent
+            /// identifiers for different subdiagnostic kinds.
             pub mod _subdiag {
+                /// Default for `#[help]`
                 pub const help: crate::SubdiagnosticMessage =
                     crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("help"));
+                /// Default for `#[note]`
                 pub const note: crate::SubdiagnosticMessage =
                     crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("note"));
+                /// Default for `#[warn]`
                 pub const warn: crate::SubdiagnosticMessage =
                     crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("warn"));
+                /// Default for `#[label]`
                 pub const label: crate::SubdiagnosticMessage =
                     crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("label"));
+                /// Default for `#[suggestion]`
                 pub const suggestion: crate::SubdiagnosticMessage =
                     crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("suggestion"));
             }
@@ -68,6 +77,11 @@ fn failed(crate_name: &Ident) -> proc_macro::TokenStream {
     .into()
 }
 
+/// Tokens to be returned when the macro cannot proceed.
+fn failed(crate_name: &Ident) -> proc_macro::TokenStream {
+    finish(quote! { pub mod #crate_name {} }, quote! { "" })
+}
+
 /// See [rustc_fluent_macro::fluent_messages].
 pub(crate) fn fluent_messages(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     let crate_name = std::env::var("CARGO_PKG_NAME")
@@ -311,39 +325,7 @@ pub(crate) fn fluent_messages(input: proc_macro::TokenStream) -> proc_macro::Tok
         }
     }
 
-    quote! {
-        /// Raw content of Fluent resource for this crate, generated by `fluent_messages` macro,
-        /// imported by `rustc_driver` to include all crates' resources in one bundle.
-        pub static DEFAULT_LOCALE_RESOURCE: &'static str = include_str!(#relative_ftl_path);
-
-        #[allow(non_upper_case_globals)]
-        #[doc(hidden)]
-        /// Auto-generated constants for type-checked references to Fluent messages.
-        pub(crate) mod fluent_generated {
-            #constants
-
-            /// Constants expected to exist by the diagnostic derive macros to use as default Fluent
-            /// identifiers for different subdiagnostic kinds.
-            pub mod _subdiag {
-                /// Default for `#[help]`
-                pub const help: crate::SubdiagnosticMessage =
-                    crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("help"));
-                /// Default for `#[note]`
-                pub const note: crate::SubdiagnosticMessage =
-                    crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("note"));
-                /// Default for `#[warn]`
-                pub const warn: crate::SubdiagnosticMessage =
-                    crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("warn"));
-                /// Default for `#[label]`
-                pub const label: crate::SubdiagnosticMessage =
-                    crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("label"));
-                /// Default for `#[suggestion]`
-                pub const suggestion: crate::SubdiagnosticMessage =
-                    crate::SubdiagnosticMessage::FluentAttr(std::borrow::Cow::Borrowed("suggestion"));
-            }
-        }
-    }
-    .into()
+    finish(constants, quote! { include_str!(#relative_ftl_path) })
 }
 
 fn variable_references<'a>(msg: &Message<&'a str>) -> Vec<&'a str> {