Auto merge of #126262 - jieyouxu:rollup-g29lo3c, r=jieyouxu

Rollup of 5 pull requests

Successful merges:

 - #125913 (Spruce up the diagnostics of some early lints)
 - #126234 (Delegation: fix ICE on late diagnostics)
 - #126253 (Simplify assert matchers in `run-make-support`)
 - #126257 (Rename `needs-matching-clang` to `needs-force-clang-based-tests`)
 - #126259 (reachable computation: clarify comments around consts)

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

compiler/rustc_expand/messages.ftl

@@ -157,7 +157,7 @@ expand_unsupported_key_value =
     key-value macro attributes are not supported
 
 expand_var_still_repeating =
-    variable '{$ident}' is still repeating at this depth
+    variable `{$ident}` is still repeating at this depth
 
 expand_wrong_fragment_kind =
     non-{$kind} macro in {$kind} position: {$name}

compiler/rustc_lint/messages.ftl

@@ -445,7 +445,8 @@ lint_macro_is_private = macro `{$ident}` is private
 lint_macro_rule_never_used = rule #{$n} of macro `{$name}` is never used
 
 lint_macro_use_deprecated =
-    deprecated `#[macro_use]` attribute used to import macros should be replaced at use sites with a `use` item to import the macro instead
+    applying the `#[macro_use]` attribute to an `extern crate` item is deprecated
+    .help = remove it and import macros at use sites with a `use` item instead
 
 lint_malformed_attribute = malformed lint attribute input
 
@@ -456,7 +457,7 @@ lint_map_unit_fn = `Iterator::map` call that discard the iterator's values
     .map_label = after this call to map, the resulting iterator is `impl Iterator<Item = ()>`, which means the only information carried by the iterator is the number of items
     .suggestion = you might have meant to use `Iterator::for_each`
 
-lint_metavariable_still_repeating = variable '{$name}' is still repeating at this depth
+lint_metavariable_still_repeating = variable `{$name}` is still repeating at this depth
 
 lint_metavariable_wrong_operator = meta-variable repeats with different Kleene operator
 
@@ -635,8 +636,8 @@ lint_pattern_in_bodiless = patterns aren't allowed in functions without bodies
 lint_pattern_in_foreign = patterns aren't allowed in foreign function declarations
     .label = pattern not allowed in foreign function
 
-lint_private_extern_crate_reexport =
-    extern crate `{$ident}` is private, and cannot be re-exported, consider declaring with `pub`
+lint_private_extern_crate_reexport = extern crate `{$ident}` is private and cannot be re-exported
+    .suggestion = consider making the `extern crate` item publicly accessible
 
 lint_proc_macro_derive_resolution_fallback = cannot find {$ns} `{$ident}` in this scope
     .label = names from parent modules are not accessible without an explicit import
@@ -847,7 +848,8 @@ lint_unused_coroutine =
     }{$post} that must be used
     .note = coroutines are lazy and do nothing unless resumed
 
-lint_unused_crate_dependency = external crate `{$extern_crate}` unused in `{$local_crate}`: remove the dependency or add `use {$extern_crate} as _;`
+lint_unused_crate_dependency = extern crate `{$extern_crate}` is unused in crate `{$local_crate}`
+    .help = remove the dependency or add `use {$extern_crate} as _;` to the crate root
 
 lint_unused_def = unused {$pre}`{$def}`{$post} that must be used
     .suggestion = use `let _ = ...` to ignore the resulting value

compiler/rustc_lint/src/context/diagnostics.rs

@@ -340,8 +340,9 @@ pub(super) fn decorate_lint(sess: &Session, diagnostic: BuiltinLintDiag, diag: &
             lints::MacroUseDeprecated.decorate_lint(diag);
         }
         BuiltinLintDiag::UnusedMacroUse => lints::UnusedMacroUse.decorate_lint(diag),
-        BuiltinLintDiag::PrivateExternCrateReexport(ident) => {
-            lints::PrivateExternCrateReexport { ident }.decorate_lint(diag);
+        BuiltinLintDiag::PrivateExternCrateReexport { source: ident, extern_crate_span } => {
+            lints::PrivateExternCrateReexport { ident, sugg: extern_crate_span.shrink_to_lo() }
+                .decorate_lint(diag);
         }
         BuiltinLintDiag::UnusedLabel => lints::UnusedLabel.decorate_lint(diag),
         BuiltinLintDiag::MacroIsPrivate(ident) => {

compiler/rustc_lint/src/lints.rs

@@ -2313,6 +2313,7 @@ pub mod unexpected_cfg_value {
 
 #[derive(LintDiagnostic)]
 #[diag(lint_macro_use_deprecated)]
+#[help]
 pub struct MacroUseDeprecated;
 
 #[derive(LintDiagnostic)]
@@ -2323,6 +2324,8 @@ pub struct UnusedMacroUse;
 #[diag(lint_private_extern_crate_reexport, code = E0365)]
 pub struct PrivateExternCrateReexport {
     pub ident: Ident,
+    #[suggestion(code = "pub ", style = "verbose", applicability = "maybe-incorrect")]
+    pub sugg: Span,
 }
 
 #[derive(LintDiagnostic)]
@@ -2416,6 +2419,7 @@ pub struct UnknownMacroVariable {
 
 #[derive(LintDiagnostic)]
 #[diag(lint_unused_crate_dependency)]
+#[help]
 pub struct UnusedCrateDependency {
     pub extern_crate: Symbol,
     pub local_crate: Symbol,

compiler/rustc_lint_defs/src/builtin.rs

@@ -511,8 +511,9 @@ declare_lint! {
     /// This will produce:
     ///
     /// ```text
-    /// error: external crate `regex` unused in `lint_example`: remove the dependency or add `use regex as _;`
+    /// error: extern crate `regex` is unused in crate `lint_example`
     ///   |
+    ///   = help: remove the dependency or add `use regex as _;` to the crate root
     /// note: the lint level is defined here
     ///  --> src/lib.rs:1:9
     ///   |
@@ -2160,8 +2161,7 @@ declare_lint! {
 }
 
 declare_lint! {
-    /// The `macro_use_extern_crate` lint detects the use of the
-    /// [`macro_use` attribute].
+    /// The `macro_use_extern_crate` lint detects the use of the [`macro_use` attribute].
     ///
     /// ### Example
     ///
@@ -2179,12 +2179,13 @@ declare_lint! {
     /// This will produce:
     ///
     /// ```text
-    /// error: deprecated `#[macro_use]` attribute used to import macros should be replaced at use sites with a `use` item to import the macro instead
+    /// error: applying the `#[macro_use]` attribute to an `extern crate` item is deprecated
     ///  --> src/main.rs:3:1
     ///   |
     /// 3 | #[macro_use]
     ///   | ^^^^^^^^^^^^
     ///   |
+    ///   = help: remove it and import macros at use sites with a `use` item instead
     /// note: the lint level is defined here
     ///  --> src/main.rs:1:9
     ///   |

compiler/rustc_lint_defs/src/lib.rs

@@ -706,7 +706,10 @@ pub enum BuiltinLintDiag {
     },
     MacroUseDeprecated,
     UnusedMacroUse,
-    PrivateExternCrateReexport(Ident),
+    PrivateExternCrateReexport {
+        source: Ident,
+        extern_crate_span: Span,
+    },
     UnusedLabel,
     MacroIsPrivate(Ident),
     UnusedMacroDefinition(Symbol),

compiler/rustc_passes/src/reachable.rs

@@ -207,18 +207,21 @@ impl<'tcx> ReachableContext<'tcx> {
                     }
 
                     hir::ItemKind::Const(_, _, init) => {
-                        // Only things actually ending up in the final constant need to be reachable.
-                        // Everything else is either already available as `mir_for_ctfe`, or can't be used
-                        // by codegen anyway.
+                        // Only things actually ending up in the final constant value are reachable
+                        // for codegen. Everything else is only needed during const-eval, so even if
+                        // const-eval happens in a downstream crate, all they need is
+                        // `mir_for_ctfe`.
                         match self.tcx.const_eval_poly_to_alloc(item.owner_id.def_id.into()) {
                             Ok(alloc) => {
                                 let alloc = self.tcx.global_alloc(alloc.alloc_id).unwrap_memory();
                                 self.propagate_from_alloc(alloc);
                             }
-                            // Reachable generic constants will be inlined into other crates
-                            // unconditionally, so we need to make sure that their
-                            // contents are also reachable.
+                            // We can't figure out which value the constant will evaluate to. In
+                            // lieu of that, we have to consider everything mentioned in the const
+                            // initializer reachable, since it *may* end up in the final value.
                             Err(ErrorHandled::TooGeneric(_)) => self.visit_nested_body(init),
+                            // If there was an error evaluating the const, nothing can be reachable
+                            // via it, and anyway compilation will fail.
                             Err(ErrorHandled::Reported(..)) => {}
                         }
                     }

compiler/rustc_resolve/src/imports.rs

@@ -259,13 +259,18 @@ struct UnresolvedImportError {
 
 // Reexports of the form `pub use foo as bar;` where `foo` is `extern crate foo;`
 // are permitted for backward-compatibility under a deprecation lint.
-fn pub_use_of_private_extern_crate_hack(import: Import<'_>, binding: NameBinding<'_>) -> bool {
+fn pub_use_of_private_extern_crate_hack(
+    import: Import<'_>,
+    binding: NameBinding<'_>,
+) -> Option<NodeId> {
     match (&import.kind, &binding.kind) {
-        (ImportKind::Single { .. }, NameBindingKind::Import { import: binding_import, .. }) => {
-            matches!(binding_import.kind, ImportKind::ExternCrate { .. })
-                && import.expect_vis().is_public()
+        (ImportKind::Single { .. }, NameBindingKind::Import { import: binding_import, .. })
+            if let ImportKind::ExternCrate { id, .. } = binding_import.kind
+                && import.expect_vis().is_public() =>
+        {
+            Some(id)
         }
-        _ => false,
+        _ => None,
     }
 }
 
@@ -275,7 +280,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
     pub(crate) fn import(&self, binding: NameBinding<'a>, import: Import<'a>) -> NameBinding<'a> {
         let import_vis = import.expect_vis().to_def_id();
         let vis = if binding.vis.is_at_least(import_vis, self.tcx)
-            || pub_use_of_private_extern_crate_hack(import, binding)
+            || pub_use_of_private_extern_crate_hack(import, binding).is_some()
         {
             import_vis
         } else {
@@ -1253,12 +1258,15 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         // All namespaces must be re-exported with extra visibility for an error to occur.
         if !any_successful_reexport {
             let (ns, binding) = reexport_error.unwrap();
-            if pub_use_of_private_extern_crate_hack(import, binding) {
+            if let Some(extern_crate_id) = pub_use_of_private_extern_crate_hack(import, binding) {
                 self.lint_buffer.buffer_lint(
                     PUB_USE_OF_PRIVATE_EXTERN_CRATE,
                     import_id,
                     import.span,
-                    BuiltinLintDiag::PrivateExternCrateReexport(ident),
+                    BuiltinLintDiag::PrivateExternCrateReexport {
+                        source: ident,
+                        extern_crate_span: self.tcx.source_span(self.local_def_id(extern_crate_id)),
+                    },
                 );
             } else {
                 if ns == TypeNS {

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -2041,8 +2041,11 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                         ast::AssocItemKind::Fn(..) => AssocSuggestion::AssocFn { called },
                         ast::AssocItemKind::Type(..) => AssocSuggestion::AssocType,
                         ast::AssocItemKind::Delegation(..)
-                            if self.r.delegation_fn_sigs[&self.r.local_def_id(assoc_item.id)]
-                                .has_self =>
+                            if self
+                                .r
+                                .delegation_fn_sigs
+                                .get(&self.r.local_def_id(assoc_item.id))
+                                .map_or(false, |sig| sig.has_self) =>
                         {
                             AssocSuggestion::MethodWithSelf { called }
                         }

src/ci/docker/host-x86_64/x86_64-gnu-debug/Dockerfile

@@ -47,7 +47,7 @@ ENV RUST_CONFIGURE_ARGS \
 # This job appears to be checking two separate things:
 # - That we can build the compiler with `--enable-debug`
 #   (without necessarily testing the result).
-# - That the tests with `//@ needs-matching-clang` pass, since they
+# - That the tests with `//@ needs-force-clang-based-tests` pass, since they
 #   don't run by default unless RUSTBUILD_FORCE_CLANG_BASED_TESTS is set.
 #   - FIXME(https://github.com/rust-lang/rust/pull/126155#issuecomment-2156314273):
 #     Currently we only run the subset of tests with "clang" in their name.

src/tools/compiletest/src/header.rs

@@ -854,9 +854,9 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "needs-asm-support",
     "needs-dlltool",
     "needs-dynamic-linking",
+    "needs-force-clang-based-tests",
     "needs-git-hash",
     "needs-llvm-components",
-    "needs-matching-clang",
     "needs-profiler-support",
     "needs-relocation-model-pic",
     "needs-run-enabled",

src/tools/compiletest/src/header/needs.rs

@@ -100,9 +100,9 @@ pub(super) fn handle_needs(
             ignore_reason: "ignored when profiler support is disabled",
         },
         Need {
-            name: "needs-matching-clang",
+            name: "needs-force-clang-based-tests",
             condition: config.run_clang_based_tests_with.is_some(),
-            ignore_reason: "ignored when the used clang does not match the built LLVM",
+            ignore_reason: "ignored when RUSTBUILD_FORCE_CLANG_BASED_TESTS is not set",
         },
         Need {
             name: "needs-xray",

src/tools/run-make-support/src/command.rs

@@ -107,38 +107,38 @@ impl CompletedProcess {
 
     /// Checks that trimmed `stdout` matches trimmed `content`.
     #[track_caller]
-    pub fn assert_stdout_equals<S: AsRef<str>>(self, content: S) -> Self {
+    pub fn assert_stdout_equals<S: AsRef<str>>(&self, content: S) -> &Self {
         assert_eq!(self.stdout_utf8().trim(), content.as_ref().trim());
         self
     }
 
     #[track_caller]
-    pub fn assert_stdout_not_contains<S: AsRef<str>>(self, needle: S) -> Self {
+    pub fn assert_stdout_not_contains<S: AsRef<str>>(&self, needle: S) -> &Self {
         assert_not_contains(&self.stdout_utf8(), needle.as_ref());
         self
     }
 
     /// Checks that trimmed `stderr` matches trimmed `content`.
     #[track_caller]
-    pub fn assert_stderr_equals<S: AsRef<str>>(self, content: S) -> Self {
+    pub fn assert_stderr_equals<S: AsRef<str>>(&self, content: S) -> &Self {
         assert_eq!(self.stderr_utf8().trim(), content.as_ref().trim());
         self
     }
 
     #[track_caller]
-    pub fn assert_stderr_contains<S: AsRef<str>>(self, needle: S) -> Self {
+    pub fn assert_stderr_contains<S: AsRef<str>>(&self, needle: S) -> &Self {
         assert!(self.stderr_utf8().contains(needle.as_ref()));
         self
     }
 
     #[track_caller]
-    pub fn assert_stderr_not_contains<S: AsRef<str>>(self, needle: S) -> Self {
+    pub fn assert_stderr_not_contains<S: AsRef<str>>(&self, needle: S) -> &Self {
         assert_not_contains(&self.stdout_utf8(), needle.as_ref());
         self
     }
 
     #[track_caller]
-    pub fn assert_exit_code(self, code: i32) -> Self {
+    pub fn assert_exit_code(&self, code: i32) -> &Self {
         assert!(self.output.status.code() == Some(code));
         self
     }

tests/run-make/cross-lang-lto-clang/Makefile

@@ -1,4 +1,4 @@
-# needs-matching-clang
+# needs-force-clang-based-tests
 
 # This test makes sure that cross-language inlining actually works by checking
 # the generated machine code.

tests/run-make/cross-lang-lto-pgo-smoketest/Makefile

@@ -1,4 +1,7 @@
-# needs-matching-clang
+# needs-force-clang-based-tests
+
+# FIXME(#126180): This test doesn't actually run anywhere, because the only
+# CI job that sets RUSTBUILD_FORCE_CLANG_BASED_TESTS runs very few tests.
 
 # This test makes sure that cross-language inlining can be used in conjunction
 # with profile-guided optimization. The test only tests that the whole workflow

tests/run-make/cross-lang-lto-riscv-abi/rmake.rs

@@ -1,8 +1,11 @@
 //! Make sure that cross-language LTO works on riscv targets,
 //! which requires extra `target-abi` metadata to be emitted.
-//@ needs-matching-clang
+//@ needs-force-clang-based-tests
 //@ needs-llvm-components riscv
 
+// FIXME(#126180): This test doesn't actually run anywhere, because the only
+// CI job that sets RUSTBUILD_FORCE_CLANG_BASED_TESTS runs very few tests.
+
 use run_make_support::{bin_name, clang, llvm_readobj, rustc};
 use std::{
     env,

tests/run-make/issue-84395-lto-embed-bitcode/Makefile

@@ -1,4 +1,7 @@
-# needs-matching-clang
+# needs-force-clang-based-tests
+
+# FIXME(#126180): This test doesn't actually run anywhere, because the only
+# CI job that sets RUSTBUILD_FORCE_CLANG_BASED_TESTS runs very few tests.
 
 # This test makes sure the embed bitcode in elf created with
 # lto-embed-bitcode=optimized is valid llvm BC module.

tests/run-make/wasm-override-linker/Makefile

@@ -1,4 +1,7 @@
-# needs-matching-clang
+# needs-force-clang-based-tests
+
+# FIXME(#126180): This test doesn't actually run anywhere, because the only
+# CI job that sets RUSTBUILD_FORCE_CLANG_BASED_TESTS runs very few tests.
 
 include ../tools.mk
 

tests/ui/delegation/ice-issue-124342.rs

@@ -0,0 +1,12 @@
+#![feature(fn_delegation)]
+#![allow(incomplete_features)]
+
+mod to_reuse {}
+
+trait Trait {
+    reuse to_reuse::foo { foo }
+    //~^ ERROR cannot find function `foo` in module `to_reuse`
+    //~| ERROR cannot find value `foo` in this scope
+}
+
+fn main() {}

tests/ui/delegation/ice-issue-124342.stderr

@@ -0,0 +1,20 @@
+error[E0425]: cannot find function `foo` in module `to_reuse`
+  --> $DIR/ice-issue-124342.rs:7:21
+   |
+LL |     reuse to_reuse::foo { foo }
+   |                     ^^^ not found in `to_reuse`
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/ice-issue-124342.rs:7:27
+   |
+LL |     reuse to_reuse::foo { foo }
+   |                           ^^^
+   |
+help: you might have meant to refer to the associated function
+   |
+LL |     reuse to_reuse::foo { Self::foo }
+   |                           ++++++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0425`.

tests/ui/extern-flag/no-nounused.rs

@@ -2,5 +2,5 @@
 //@ compile-flags: -Zunstable-options -Dunused-crate-dependencies
 //@ edition:2018
 
-fn main() { //~ ERROR external crate `somedep` unused in `no_nounused`
+fn main() { //~ ERROR extern crate `somedep` is unused in crate `no_nounused`
 }