Auto merge of #135678 - matthiaskrgr:rollup-psuyzpn, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #134455 (cleanup promoteds move check)
 - #135421 (Make tidy warn on unrecognized directives)
 - #135611 (Remove unnecessary assertion for reference error)
 - #135620 (ci: improve github action name)
 - #135639 (new solver: prefer trivial builtin impls)
 - #135654 (add src/librustdoc and src/rustdoc-json-types to RUSTC_IF_UNCHANGED_ALLOWED_PATHS)

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

Author: bors

Diff for: .github/workflows/ghcr.yml

@@ -9,7 +9,7 @@
 # for PR jobs, because forks can't access secrets.
 # That's why we use ghcr.io: it has no rate limit and it doesn't require authentication.
 
-name: GHCR
+name: GHCR image mirroring
 
 on:
   workflow_dispatch:

Diff for: Cargo.lock

@@ -4259,6 +4259,7 @@ dependencies = [
  "rustc_serialize",
  "rustc_type_ir",
  "rustc_type_ir_macros",
+ "smallvec",
  "tracing",
 ]
 

Diff for: compiler/rustc_borrowck/src/lib.rs

@@ -182,9 +182,6 @@ fn do_mir_borrowck<'tcx>(
     let location_table = PoloniusLocationTable::new(body);
 
     let move_data = MoveData::gather_moves(body, tcx, |_| true);
-    let promoted_move_data = promoted
-        .iter_enumerated()
-        .map(|(idx, body)| (idx, MoveData::gather_moves(body, tcx, |_| true)));
 
     let flow_inits = MaybeInitializedPlaces::new(tcx, body, &move_data)
         .iterate_to_fixpoint(tcx, body, Some("borrowck"))
@@ -242,10 +239,14 @@ fn do_mir_borrowck<'tcx>(
         false
     };
 
-    for (idx, move_data) in promoted_move_data {
+    // While promoteds should mostly be correct by construction, we need to check them for
+    // invalid moves to detect moving out of arrays:`struct S; fn main() { &([S][0]); }`.
+    for promoted_body in &promoted {
         use rustc_middle::mir::visit::Visitor;
-
-        let promoted_body = &promoted[idx];
+        // This assumes that we won't use some of the fields of the `promoted_mbcx`
+        // when detecting and reporting move errors. While it would be nice to move
+        // this check out of `MirBorrowckCtxt`, actually doing so is far from trivial.
+        let move_data = MoveData::gather_moves(promoted_body, tcx, |_| true);
         let mut promoted_mbcx = MirBorrowckCtxt {
             infcx: &infcx,
             body: promoted_body,
@@ -270,9 +271,6 @@ fn do_mir_borrowck<'tcx>(
             move_errors: Vec::new(),
             diags_buffer,
         };
-        MoveVisitor { ctxt: &mut promoted_mbcx }.visit_body(promoted_body);
-        promoted_mbcx.report_move_errors();
-
         struct MoveVisitor<'a, 'b, 'infcx, 'tcx> {
             ctxt: &'a mut MirBorrowckCtxt<'b, 'infcx, 'tcx>,
         }
@@ -284,6 +282,8 @@ fn do_mir_borrowck<'tcx>(
                 }
             }
         }
+        MoveVisitor { ctxt: &mut promoted_mbcx }.visit_body(promoted_body);
+        promoted_mbcx.report_move_errors();
     }
 
     let mut mbcx = MirBorrowckCtxt {

Diff for: compiler/rustc_hir_analysis/src/check/check.rs

@@ -1637,7 +1637,6 @@ fn check_type_alias_type_params_are_used<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalD
     let ty = tcx.type_of(def_id).instantiate_identity();
     if ty.references_error() {
         // If there is already another error, do not emit an error for not using a type parameter.
-        assert!(tcx.dcx().has_errors().is_some());
         return;
     }
 

Diff for: compiler/rustc_next_trait_solver/Cargo.toml

@@ -13,6 +13,7 @@ rustc_macros = { path = "../rustc_macros", optional = true }
 rustc_serialize = { path = "../rustc_serialize", optional = true }
 rustc_type_ir = { path = "../rustc_type_ir", default-features = false }
 rustc_type_ir_macros = { path = "../rustc_type_ir_macros" }
+smallvec = "1.8.1"
 tracing = "0.1"
 # tidy-alphabetical-end
 

Diff for: compiler/rustc_next_trait_solver/src/solve/trait_goals.rs

@@ -8,6 +8,7 @@ use rustc_type_ir::lang_items::TraitSolverLangItem;
 use rustc_type_ir::solve::CanonicalResponse;
 use rustc_type_ir::visit::TypeVisitableExt as _;
 use rustc_type_ir::{self as ty, Interner, TraitPredicate, TypingMode, Upcast as _, elaborate};
+use smallvec::SmallVec;
 use tracing::{instrument, trace};
 
 use crate::delegate::SolverDelegate;
@@ -225,7 +226,7 @@ where
         }
 
         ecx.probe_and_evaluate_goal_for_constituent_tys(
-            CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
+            CandidateSource::BuiltinImpl(BuiltinImplSource::Trivial),
             goal,
             structural_traits::instantiate_constituent_tys_for_sized_trait,
         )
@@ -1194,7 +1195,30 @@ where
             };
         }
 
-        // FIXME: prefer trivial builtin impls
+        // We prefer trivial builtin candidates, i.e. builtin impls without any
+        // nested requirements, over all others. This is a fix for #53123 and
+        // prevents where-bounds from accidentally extending the lifetime of a
+        // variable.
+        if candidates
+            .iter()
+            .any(|c| matches!(c.source, CandidateSource::BuiltinImpl(BuiltinImplSource::Trivial)))
+        {
+            let trivial_builtin_impls: SmallVec<[_; 1]> = candidates
+                .iter()
+                .filter(|c| {
+                    matches!(c.source, CandidateSource::BuiltinImpl(BuiltinImplSource::Trivial))
+                })
+                .map(|c| c.result)
+                .collect();
+            // There should only ever be a single trivial builtin candidate
+            // as they would otherwise overlap.
+            assert_eq!(trivial_builtin_impls.len(), 1);
+            return if let Some(response) = self.try_merge_responses(&trivial_builtin_impls) {
+                Ok((response, Some(TraitGoalProvenVia::Misc)))
+            } else {
+                Ok((self.bail_with_ambiguity(&trivial_builtin_impls), None))
+            };
+        }
 
         // If there are non-global where-bounds, prefer where-bounds
         // (including global ones) over everything else.

Diff for: compiler/rustc_trait_selection/src/traits/project.rs

@@ -991,7 +991,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
                     Err(ErrorGuaranteed { .. }) => true,
                 }
             }
-            ImplSource::Builtin(BuiltinImplSource::Misc, _) => {
+            ImplSource::Builtin(BuiltinImplSource::Misc | BuiltinImplSource::Trivial, _) => {
                 // While a builtin impl may be known to exist, the associated type may not yet
                 // be known. Any type with multiple potential associated types is therefore
                 // not eligible.
@@ -1296,7 +1296,7 @@ fn confirm_select_candidate<'cx, 'tcx>(
 ) -> Progress<'tcx> {
     match impl_source {
         ImplSource::UserDefined(data) => confirm_impl_candidate(selcx, obligation, data),
-        ImplSource::Builtin(BuiltinImplSource::Misc, data) => {
+        ImplSource::Builtin(BuiltinImplSource::Misc | BuiltinImplSource::Trivial, data) => {
             let tcx = selcx.tcx();
             let trait_def_id = obligation.predicate.trait_def_id(tcx);
             if tcx.is_lang_item(trait_def_id, LangItem::Coroutine) {

Diff for: compiler/rustc_ty_utils/src/instance.rs

@@ -248,7 +248,7 @@ fn resolve_associated_item<'tcx>(
                 })
             }
         }
-        traits::ImplSource::Builtin(BuiltinImplSource::Misc, _) => {
+        traits::ImplSource::Builtin(BuiltinImplSource::Misc | BuiltinImplSource::Trivial, _) => {
             if tcx.is_lang_item(trait_ref.def_id, LangItem::Clone) {
                 // FIXME(eddyb) use lang items for methods instead of names.
                 let name = tcx.item_name(trait_item_id);

Diff for: compiler/rustc_type_ir/src/solve/mod.rs

@@ -169,6 +169,9 @@ pub enum CandidateSource<I: Interner> {
 #[derive(Clone, Copy, Hash, PartialEq, Eq, Debug)]
 #[cfg_attr(feature = "nightly", derive(HashStable_NoContext, TyEncodable, TyDecodable))]
 pub enum BuiltinImplSource {
+    /// A built-in impl that is considered trivial, without any nested requirements. They
+    /// are preferred over where-clauses, and we want to track them explicitly.
+    Trivial,
     /// Some built-in impl we don't need to differentiate. This should be used
     /// unless more specific information is necessary.
     Misc,

Diff for: src/bootstrap/src/core/config/config.rs

@@ -42,6 +42,8 @@ use crate::utils::helpers::{self, exe, output, t};
 #[rustfmt::skip] // We don't want rustfmt to oneline this list
 pub(crate) const RUSTC_IF_UNCHANGED_ALLOWED_PATHS: &[&str] = &[
     ":!src/tools",
+    ":!src/librustdoc",
+    ":!src/rustdoc-json-types",
     ":!tests",
     ":!triagebot.toml",
 ];

Diff for: src/tools/compiletest/src/runtest.rs

@@ -32,7 +32,7 @@ use crate::{ColorConfig, json, stamp_file_path};
 mod debugger;
 
 // Helper modules that implement test running logic for each test suite.
-// tidy-alphabet-start
+// tidy-alphabetical-start
 mod assembly;
 mod codegen;
 mod codegen_units;
@@ -47,7 +47,7 @@ mod run_make;
 mod rustdoc;
 mod rustdoc_json;
 mod ui;
-// tidy-alphabet-end
+// tidy-alphabetical-end
 
 #[cfg(test)]
 mod tests;

Diff for: src/tools/tidy/src/style.rs

@@ -72,6 +72,21 @@ const ANNOTATIONS_TO_IGNORE: &[&str] = &[
     "//@ normalize-stderr",
 ];
 
+// If you edit this, also edit where it gets used in `check` (calling `contains_ignore_directives`)
+const CONFIGURABLE_CHECKS: [&str; 11] = [
+    "cr",
+    "undocumented-unsafe",
+    "tab",
+    "linelength",
+    "filelength",
+    "end-whitespace",
+    "trailing-newlines",
+    "leading-newlines",
+    "copyright",
+    "dbg",
+    "odd-backticks",
+];
+
 fn generate_problems<'a>(
     consts: &'a [u32],
     letter_digit: &'a FxHashMap<char, char>,
@@ -220,6 +235,7 @@ fn long_line_is_ok(extension: &str, is_error_code: bool, max_columns: usize, lin
     }
 }
 
+#[derive(Clone, Copy)]
 enum Directive {
     /// By default, tidy always warns against style issues.
     Deny,
@@ -231,20 +247,28 @@ enum Directive {
     Ignore(bool),
 }
 
-fn contains_ignore_directive(can_contain: bool, contents: &str, check: &str) -> Directive {
+// Use a fixed size array in the return type to catch mistakes with changing `CONFIGURABLE_CHECKS`
+// without changing the code in `check` easier.
+fn contains_ignore_directives<const N: usize>(
+    can_contain: bool,
+    contents: &str,
+    checks: [&str; N],
+) -> [Directive; N] {
     if !can_contain {
-        return Directive::Deny;
-    }
-    // Update `can_contain` when changing this
-    if contents.contains(&format!("// ignore-tidy-{check}"))
-        || contents.contains(&format!("# ignore-tidy-{check}"))
-        || contents.contains(&format!("/* ignore-tidy-{check} */"))
-        || contents.contains(&format!("<!-- ignore-tidy-{check} -->"))
-    {
-        Directive::Ignore(false)
-    } else {
-        Directive::Deny
+        return [Directive::Deny; N];
     }
+    checks.map(|check| {
+        // Update `can_contain` when changing this
+        if contents.contains(&format!("// ignore-tidy-{check}"))
+            || contents.contains(&format!("# ignore-tidy-{check}"))
+            || contents.contains(&format!("/* ignore-tidy-{check} */"))
+            || contents.contains(&format!("<!-- ignore-tidy-{check} -->"))
+        {
+            Directive::Ignore(false)
+        } else {
+            Directive::Deny
+        }
+    })
 }
 
 macro_rules! suppressible_tidy_err {
@@ -370,6 +394,7 @@ pub fn check(path: &Path, bad: &mut bool) {
             COLS
         };
 
+        // When you change this, also change the `directive_line_starts` variable below
         let can_contain = contents.contains("// ignore-tidy-")
             || contents.contains("# ignore-tidy-")
             || contents.contains("/* ignore-tidy-")
@@ -385,22 +410,19 @@ pub fn check(path: &Path, bad: &mut bool) {
                 return;
             }
         }
-        let mut skip_cr = contains_ignore_directive(can_contain, &contents, "cr");
-        let mut skip_undocumented_unsafe =
-            contains_ignore_directive(can_contain, &contents, "undocumented-unsafe");
-        let mut skip_tab = contains_ignore_directive(can_contain, &contents, "tab");
-        let mut skip_line_length = contains_ignore_directive(can_contain, &contents, "linelength");
-        let mut skip_file_length = contains_ignore_directive(can_contain, &contents, "filelength");
-        let mut skip_end_whitespace =
-            contains_ignore_directive(can_contain, &contents, "end-whitespace");
-        let mut skip_trailing_newlines =
-            contains_ignore_directive(can_contain, &contents, "trailing-newlines");
-        let mut skip_leading_newlines =
-            contains_ignore_directive(can_contain, &contents, "leading-newlines");
-        let mut skip_copyright = contains_ignore_directive(can_contain, &contents, "copyright");
-        let mut skip_dbg = contains_ignore_directive(can_contain, &contents, "dbg");
-        let mut skip_odd_backticks =
-            contains_ignore_directive(can_contain, &contents, "odd-backticks");
+        let [
+            mut skip_cr,
+            mut skip_undocumented_unsafe,
+            mut skip_tab,
+            mut skip_line_length,
+            mut skip_file_length,
+            mut skip_end_whitespace,
+            mut skip_trailing_newlines,
+            mut skip_leading_newlines,
+            mut skip_copyright,
+            mut skip_dbg,
+            mut skip_odd_backticks,
+        ] = contains_ignore_directives(can_contain, &contents, CONFIGURABLE_CHECKS);
         let mut leading_new_lines = false;
         let mut trailing_new_lines = 0;
         let mut lines = 0;
@@ -474,6 +496,22 @@ pub fn check(path: &Path, bad: &mut bool) {
                 suppressible_tidy_err!(err, skip_cr, "CR character");
             }
             if !is_this_file {
+                let directive_line_starts = ["// ", "# ", "/* ", "<!-- "];
+                let possible_line_start =
+                    directive_line_starts.into_iter().any(|s| line.starts_with(s));
+                let contains_potential_directive =
+                    possible_line_start && (line.contains("-tidy") || line.contains("tidy-"));
+                let has_recognized_ignore_directive =
+                    contains_ignore_directives(can_contain, line, CONFIGURABLE_CHECKS)
+                        .into_iter()
+                        .any(|directive| matches!(directive, Directive::Ignore(_)));
+                let has_alphabetical_directive = line.contains("tidy-alphabetical-start")
+                    || line.contains("tidy-alphabetical-end");
+                let has_recognized_directive =
+                    has_recognized_ignore_directive || has_alphabetical_directive;
+                if contains_potential_directive && (!has_recognized_directive) {
+                    err("Unrecognized tidy directive")
+                }
                 // Allow using TODO in diagnostic suggestions by marking the
                 // relevant line with `// ignore-tidy-todo`.
                 if trimmed.contains("TODO") && !trimmed.contains("ignore-tidy-todo") {

Diff for: tests/crashes/135341.rs

@@ -1,4 +1,7 @@
-//@ run-pass
+//@ revisions: current next
+//@ [next] compile-flags: -Znext-solver
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@ check-pass
 
 pub trait Foo<T> {
     fn foo(self) -> T;

Diff for: tests/ui/regions/issue-26448-1.rs

@@ -1,3 +1,6 @@
+//@ revisions: current next
+//@ [next] compile-flags: -Znext-solver
+//@ ignore-compare-mode-next-solver (explicit revisions)
 //@ check-pass
 
 pub struct Bar<T> {

Diff for: tests/ui/regions/issue-26448-2.rs

@@ -0,0 +1,4 @@
+type A<T> = B;
+type B = _; //~ ERROR the placeholder `_` is not allowed within types on item signatures for type aliases
+
+fn main() {}

Diff for: tests/ui/wf/ice-hir-wf-issue-135341.rs

@@ -0,0 +1,9 @@
+error[E0121]: the placeholder `_` is not allowed within types on item signatures for type aliases
+  --> $DIR/ice-hir-wf-issue-135341.rs:2:10
+   |
+LL | type B = _;
+   |          ^ not allowed in type signatures
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0121`.