Auto merge of #67770 - Centril:reduce-diversity-2, r=petrochenkov

More reductions in error handling diversity

In this follow up to #67744, we:

- Remove all fatal / error / warning macros in `syntax` except for `struct_span_err`, which is moved to `rustc_errors`.

- Lintify some hard-coded warnings which used warning macros.

- Defatalize some errors.

In general, the goal here is to make it painful to use fatal or unstructured errors and so we hopefully won't see many of these creep in.

Fixes #67933.

Author: bors

Cargo.lock

@@ -3804,6 +3804,7 @@ version = "0.0.0"
 dependencies = [
  "rustc",
  "rustc_error_codes",
+ "rustc_errors",
  "rustc_hir",
  "rustc_metadata",
  "rustc_span",
@@ -3818,6 +3819,7 @@ dependencies = [
  "rustc",
  "rustc_data_structures",
  "rustc_error_codes",
+ "rustc_errors",
  "rustc_hir",
  "rustc_span",
  "rustc_typeck",

src/librustc/hir/check_attr.rs

@@ -8,6 +8,8 @@ use crate::hir::intravisit::{self, NestedVisitorMap, Visitor};
 use crate::lint::builtin::UNUSED_ATTRIBUTES;
 use crate::ty::query::Providers;
 use crate::ty::TyCtxt;
+
+use errors::struct_span_err;
 use rustc_error_codes::*;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
@@ -430,21 +432,27 @@ impl CheckAttrVisitor<'tcx> {
         // Error on repr(transparent, <anything else>).
         if is_transparent && hints.len() > 1 {
             let hint_spans: Vec<_> = hint_spans.clone().collect();
-            span_err!(
+            struct_span_err!(
                 self.tcx.sess,
                 hint_spans,
                 E0692,
                 "transparent {} cannot have other repr hints",
                 target
-            );
+            )
+            .emit();
         }
         // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
         if (int_reprs > 1)
             || (is_simd && is_c)
             || (int_reprs == 1 && is_c && item.map_or(false, |item| is_c_like_enum(item)))
         {
-            let hint_spans: Vec<_> = hint_spans.collect();
-            span_warn!(self.tcx.sess, hint_spans, E0566, "conflicting representation hints");
+            struct_span_err!(
+                self.tcx.sess,
+                hint_spans.collect::<Vec<Span>>(),
+                E0566,
+                "conflicting representation hints",
+            )
+            .emit();
         }
     }