Rollup merge of #121085 - davidtwco:always-eager-diagnostics, r=nnethercote

errors: only eagerly translate subdiagnostics

Subdiagnostics don't need to be lazily translated, they can always be eagerly translated. Eager translation is slightly more complex as we need to have a `DiagCtxt` available to perform the translation, which involves slightly more threading of that context.

This slight increase in complexity should enable later simplifications - like passing `DiagCtxt` into `AddToDiagnostic` and moving Fluent messages into the diagnostic structs rather than having them in separate files (working on that was what led to this change).

r? ```@nnethercote```

1 files changed, 1 insertions, 1 deletions

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 69518287f38..ce0421ef62d 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -2350,7 +2350,7 @@ impl<'a> Parser<'a> {
         let mut err = self.dcx().struct_span_err(span, msg);
         let sp = self.sess.source_map().start_point(self.token.span);
         if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&sp) {
-            err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
+            err.subdiagnostic(self.dcx(), ExprParenthesesNeeded::surrounding(*sp));
         }
         err.span_label(span, "expected expression");