Prefer `DiagnosticBuilder` over `Diagnostic` in diagnostic modifiers.

There are lots of functions that modify a diagnostic. This can be via a
`&mut Diagnostic` or a `&mut DiagnosticBuilder`, because the latter type
wraps the former and impls `DerefMut`.

This commit converts all the `&mut Diagnostic` occurrences to `&mut
DiagnosticBuilder`. This is a step towards greatly simplifying
`Diagnostic`. Some of the relevant function are made generic, because
they deal with both errors and warnings. No function bodies are changed,
because all the modifier methods are available on both `Diagnostic` and
`DiagnosticBuilder`.

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler/rustc_hir_analysis/src/astconv/errors.rs b/compiler/rustc_hir_analysis/src/astconv/errors.rs
index ad34c31ef8f..214d9602968 100644
--- a/compiler/rustc_hir_analysis/src/astconv/errors.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/errors.rs
@@ -9,7 +9,7 @@ use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_data_structures::unord::UnordMap;
 use rustc_errors::{
-    codes::*, pluralize, struct_span_code_err, Applicability, Diagnostic, ErrorGuaranteed,
+    codes::*, pluralize, struct_span_code_err, Applicability, DiagnosticBuilder, ErrorGuaranteed,
 };
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -371,7 +371,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     // FIXME(fmease): Heavily adapted from `rustc_hir_typeck::method::suggest`. Deduplicate.
     fn note_ambiguous_inherent_assoc_type(
         &self,
-        err: &mut Diagnostic,
+        err: &mut DiagnosticBuilder<'_>,
         candidates: Vec<DefId>,
         span: Span,
     ) {
@@ -429,7 +429,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let tcx = self.tcx();
 
         let adt_did = self_ty.ty_adt_def().map(|def| def.did());
-        let add_def_label = |err: &mut Diagnostic| {
+        let add_def_label = |err: &mut DiagnosticBuilder<'_>| {
             if let Some(did) = adt_did {
                 err.span_label(
                     tcx.def_span(did),