Auto merge of #123540 - matthiaskrgr:rollup-8ewq0zt, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #123294 (Require LLVM_CONFIG to be set in rustc_llvm/build.rs)
 - #123467 (MSVC targets should use COFF as their archive format)
 - #123498 (explaining `DefKind::Field`)
 - #123519 (Improve cfg and check-cfg configuration)
 - #123525 (CFI: Don't rewrite ty::Dynamic directly)
 - #123526 (Do not ICE when calling incorrectly defined `transmute` intrinsic)
 - #123528 (Hide async_gen_internals from standard library documentation)

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

Author: bors

compiler/rustc_codegen_ssa/src/back/archive.rs

@@ -231,7 +231,11 @@ impl<'a> ArArchiveBuilder<'a> {
             "gnu" => ArchiveKind::Gnu,
             "bsd" => ArchiveKind::Bsd,
             "darwin" => ArchiveKind::Darwin,
-            "coff" => ArchiveKind::Coff,
+            "coff" => {
+                // FIXME: ar_archive_writer doesn't support COFF archives yet.
+                // https://github.com/rust-lang/ar_archive_writer/issues/9
+                ArchiveKind::Gnu
+            }
             "aix_big" => ArchiveKind::AixBig,
             kind => {
                 self.sess.dcx().emit_fatal(UnknownArchiveKind { kind });

compiler/rustc_hir/src/def.rs

@@ -113,6 +113,9 @@ pub enum DefKind {
     InlineConst,
     /// Opaque type, aka `impl Trait`.
     OpaqueTy,
+    /// A field in a struct, enum or union. e.g.
+    /// - `bar` in `struct Foo { bar: u8 }`
+    /// - `Foo::Bar::0` in `enum Foo { Bar(u8) }`
     Field,
     /// Lifetime parameter: the `'a` in `struct Foo<'a> { ... }`
     LifetimeParam,

compiler/rustc_hir_typeck/src/expr.rs

@@ -544,13 +544,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             if tcx.fn_sig(did).skip_binder().abi() == RustIntrinsic
                 && tcx.item_name(did) == sym::transmute
             {
-                let from = fn_sig.inputs().skip_binder()[0];
+                let Some(from) = fn_sig.inputs().skip_binder().get(0) else {
+                    let e = self.dcx().span_delayed_bug(
+                        tcx.def_span(did),
+                        "intrinsic fn `transmute` defined with no parameters",
+                    );
+                    self.set_tainted_by_errors(e);
+                    return Ty::new_error(tcx, e);
+                };
                 let to = fn_sig.output().skip_binder();
                 // We defer the transmute to the end of typeck, once all inference vars have
                 // been resolved or we errored. This is important as we can only check transmute
                 // on concrete types, but the output type may not be known yet (it would only
                 // be known if explicitly specified via turbofish).
-                self.deferred_transmute_checks.borrow_mut().push((from, to, expr.hir_id));
+                self.deferred_transmute_checks.borrow_mut().push((*from, to, expr.hir_id));
             }
             if !tcx.features().unsized_fn_params {
                 // We want to remove some Sized bounds from std functions,

compiler/rustc_llvm/build.rs

@@ -112,28 +112,10 @@ fn main() {
 
     restore_library_path();
 
-    let target = env::var("TARGET").expect("TARGET was not set");
     let llvm_config =
-        tracked_env_var_os("LLVM_CONFIG").map(|x| Some(PathBuf::from(x))).unwrap_or_else(|| {
-            if let Some(dir) = tracked_env_var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
-                let to_test = dir
-                    .parent()
-                    .unwrap()
-                    .parent()
-                    .unwrap()
-                    .join(&target)
-                    .join("llvm/bin/llvm-config");
-                if Command::new(&to_test).output().is_ok() {
-                    return Some(to_test);
-                }
-            }
-            None
-        });
+        PathBuf::from(tracked_env_var_os("LLVM_CONFIG").expect("LLVM_CONFIG was not set"));
 
-    if let Some(llvm_config) = &llvm_config {
-        println!("cargo:rerun-if-changed={}", llvm_config.display());
-    }
-    let llvm_config = llvm_config.unwrap_or_else(|| PathBuf::from("llvm-config"));
+    println!("cargo:rerun-if-changed={}", llvm_config.display());
 
     // Test whether we're cross-compiling LLVM. This is a pretty rare case
     // currently where we're producing an LLVM for a different platform than