Rename DiagnosticBuilder as Diag.

Much better!

Note that this involves renaming (and updating the value of)
`DIAGNOSTIC_BUILDER` in clippy.

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -1,7 +1,7 @@
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
 
-use rustc_errors::{Applicability, DiagnosticBuilder};
+use rustc_errors::{Applicability, Diag};
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty};
 use rustc_mir_dataflow::move_paths::{LookupResult, MovePathIndex};
@@ -287,11 +287,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         self.buffer_error(err);
     }
 
-    fn report_cannot_move_from_static(
-        &mut self,
-        place: Place<'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx> {
+    fn report_cannot_move_from_static(&mut self, place: Place<'tcx>, span: Span) -> Diag<'tcx> {
         let description = if place.projection.len() == 1 {
             format!("static item {}", self.describe_any_place(place.as_ref()))
         } else {
@@ -313,7 +309,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         deref_target_place: Place<'tcx>,
         span: Span,
         use_spans: Option<UseSpans<'tcx>>,
-    ) -> DiagnosticBuilder<'tcx> {
+    ) -> Diag<'tcx> {
         // Inspect the type of the content behind the
         // borrow to provide feedback about why this
         // was a move rather than a copy.
@@ -437,12 +433,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         err
     }
 
-    fn add_move_hints(
-        &self,
-        error: GroupedMoveError<'tcx>,
-        err: &mut DiagnosticBuilder<'_>,
-        span: Span,
-    ) {
+    fn add_move_hints(&self, error: GroupedMoveError<'tcx>, err: &mut Diag<'_>, span: Span) {
         match error {
             GroupedMoveError::MovesFromPlace { mut binds_to, move_from, .. } => {
                 self.add_borrow_suggestions(err, span);
@@ -505,7 +496,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         }
     }
 
-    fn add_borrow_suggestions(&self, err: &mut DiagnosticBuilder<'_>, span: Span) {
+    fn add_borrow_suggestions(&self, err: &mut Diag<'_>, span: Span) {
         match self.infcx.tcx.sess.source_map().span_to_snippet(span) {
             Ok(snippet) if snippet.starts_with('*') => {
                 err.span_suggestion_verbose(
@@ -526,7 +517,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         }
     }
 
-    fn add_move_error_suggestions(&self, err: &mut DiagnosticBuilder<'_>, binds_to: &[Local]) {
+    fn add_move_error_suggestions(&self, err: &mut Diag<'_>, binds_to: &[Local]) {
         let mut suggestions: Vec<(Span, String, String)> = Vec::new();
         for local in binds_to {
             let bind_to = &self.body.local_decls[*local];
@@ -578,7 +569,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         }
     }
 
-    fn add_move_error_details(&self, err: &mut DiagnosticBuilder<'_>, binds_to: &[Local]) {
+    fn add_move_error_details(&self, err: &mut Diag<'_>, binds_to: &[Local]) {
         for (j, local) in binds_to.iter().enumerate() {
             let bind_to = &self.body.local_decls[*local];
             let binding_span = bind_to.source_info.span;
@@ -615,7 +606,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     /// expansion of a packed struct.
     /// Such errors happen because derive macro expansions shy away from taking
     /// references to the struct's fields since doing so would be undefined behaviour
-    fn add_note_for_packed_struct_derive(&self, err: &mut DiagnosticBuilder<'_>, local: Local) {
+    fn add_note_for_packed_struct_derive(&self, err: &mut Diag<'_>, local: Local) {
         let local_place: PlaceRef<'tcx> = local.into();
         let local_ty = local_place.ty(self.body.local_decls(), self.infcx.tcx).ty.peel_refs();