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```

4 files changed, 11 insertions, 8 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");
 
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 2424b6c130d..20b9581f2ef 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1433,7 +1433,7 @@ impl<'a> Parser<'a> {
                     // If the input is something like `if a { 1 } else { 2 } | if a { 3 } else { 4 }`
                     // then suggest parens around the lhs.
                     if let Some(sp) = this.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
-                        err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
+                        err.subdiagnostic(this.dcx(), ExprParenthesesNeeded::surrounding(*sp));
                     }
                     err
                 })
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index a0605b8a44c..e7b9076bd3c 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -1933,7 +1933,7 @@ impl<'a> Parser<'a> {
         if self.token.kind == token::Not {
             if let Err(mut err) = self.unexpected::<FieldDef>() {
                 // Encounter the macro invocation
-                err.subdiagnostic(MacroExpandsToAdtField { adt_ty });
+                err.subdiagnostic(self.dcx(), MacroExpandsToAdtField { adt_ty });
                 return Err(err);
             }
         }
@@ -2352,10 +2352,13 @@ impl<'a> Parser<'a> {
                             .into_iter()
                             .any(|s| self.prev_token.is_ident_named(s));
 
-                        err.subdiagnostic(errors::FnTraitMissingParen {
-                            span: self.prev_token.span,
-                            machine_applicable,
-                        });
+                        err.subdiagnostic(
+                            self.dcx(),
+                            errors::FnTraitMissingParen {
+                                span: self.prev_token.span,
+                                machine_applicable,
+                            },
+                        );
                     }
                     return Err(err);
                 }
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 12260ec95a5..75fc013d3e6 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -843,7 +843,7 @@ impl<'a> Parser<'a> {
 
         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(err)