Convert to inline diagnostics in rustc_infer

compiler/rustc_infer/Cargo.toml

@@ -10,7 +10,6 @@ doctest = false
 # tidy-alphabetical-start
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
-rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }

compiler/rustc_infer/messages.ftl

@@ -1,5 +0,0 @@
-infer_opaque_hidden_type =
-    opaque type's hidden type cannot be another opaque type from the same scope
-    .label = one of the two opaque types used here has to be outside its defining scope
-    .opaque_type = opaque type whose hidden type is being assigned
-    .hidden_type = opaque type being used as hidden type

compiler/rustc_infer/src/errors.rs

@@ -2,13 +2,13 @@ use rustc_macros::Diagnostic;
 use rustc_span::Span;
 
 #[derive(Diagnostic)]
-#[diag(infer_opaque_hidden_type)]
+#[diag("opaque type's hidden type cannot be another opaque type from the same scope")]
 pub(crate) struct OpaqueHiddenTypeDiag {
     #[primary_span]
-    #[label]
+    #[label("one of the two opaque types used here has to be outside its defining scope")]
     pub span: Span,
-    #[note(infer_opaque_type)]
+    #[note("opaque type whose hidden type is being assigned")]
     pub opaque_type: Span,
-    #[note(infer_hidden_type)]
+    #[note("opaque type being used as hidden type")]
     pub hidden_type: Span,
 }

compiler/rustc_infer/src/lib.rs

@@ -22,5 +22,3 @@
 mod errors;
 pub mod infer;
 pub mod traits;
-
-rustc_fluent_macro::fluent_messages! { "../messages.ftl" }