Auto merge of #100611 - matthiaskrgr:rollup-rxj10ur, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #100338 (when there are 3 or more return statements in the loop)
 - #100384 (Add support for generating unique profraw files by default when using `-C instrument-coverage`)
 - #100460 (Update the minimum external LLVM to 13)
 - #100567 (Add missing closing quote)
 - #100590 (Suggest adding an array length if possible)
 - #100600 (Rename Machine memory hooks to suggest when they run)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

.github/workflows/ci.yml

@@ -43,7 +43,7 @@ jobs:
           - name: mingw-check
             os: ubuntu-20.04-xl
             env: {}
-          - name: x86_64-gnu-llvm-12
+          - name: x86_64-gnu-llvm-13
             os: ubuntu-20.04-xl
             env: {}
           - name: x86_64-gnu-tools
@@ -274,11 +274,11 @@ jobs:
           - name: x86_64-gnu-distcheck
             os: ubuntu-20.04-xl
             env: {}
-          - name: x86_64-gnu-llvm-12
+          - name: x86_64-gnu-llvm-13
             env:
               RUST_BACKTRACE: 1
             os: ubuntu-20.04-xl
-          - name: x86_64-gnu-llvm-12-stage1
+          - name: x86_64-gnu-llvm-13-stage1
             env:
               RUST_BACKTRACE: 1
             os: ubuntu-20.04-xl

compiler/rustc_ast_lowering/src/lib.rs

@@ -48,7 +48,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::Lrc;
-use rustc_errors::{struct_span_err, Applicability, Handler};
+use rustc_errors::{struct_span_err, Applicability, Handler, StashKey};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
 use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
@@ -2233,7 +2233,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         c.value.span,
                         "using `_` for array lengths is unstable",
                     )
-                    .emit();
+                    .stash(c.value.span, StashKey::UnderscoreForArrayLengths);
                     hir::ArrayLen::Body(self.lower_anon_const(c))
                 }
             }