Auto merge of #65793 - Centril:rollup-v40xke9, r=Centril

Rollup of 9 pull requests

Successful merges:

 - #62959 (Add by-value iterator for arrays )
 - #65390 (Add long error explanation for E0576)
 - #65408 (reorder config.toml.example options and add one missing option)
 - #65414 (ignore uninhabited non-exhaustive variant fields)
 - #65666 (Deprecated proc_macro doesn't trigger warning on build library)
 - #65742 (Pre-expansion gate most of the things)
 - #65747 (Adjust the tracking issue for `untagged_unions`.)
 - #65763 (Changed APIT with explicit generic args span to specific arg spans)
 - #65775 (Fix more `ReEmpty` ICEs)

Failed merges:

 - #65519 (trait-based structural match implementation)

r? @ghost

config.toml.example

@@ -258,10 +258,9 @@
 [rust]
 
 # Whether or not to optimize the compiler and standard library.
-#
-# Note: the slowness of the non optimized compiler compiling itself usually
-#       outweighs the time gains in not doing optimizations, therefore a
-#       full bootstrap takes much more time with `optimize` set to false.
+# WARNING: Building with optimize = false is NOT SUPPORTED. Due to bootstrapping,
+# building without optimizations takes much longer than optimizing. Further, some platforms
+# fail to build without this optimization (c.f. #65352).
 #optimize = true
 
 # Indicates that the build should be configured for debugging Rust. A
@@ -341,6 +340,9 @@
 # nightly features
 #channel = "dev"
 
+# The root location of the MUSL installation directory.
+#musl-root = "..."
+
 # By default the `rustc` executable is built with `-Wl,-rpath` flags on Unix
 # platforms to ensure that the compiler is usable by default from the build
 # directory (as it links to a number of dynamic libraries). This may not be

src/bootstrap/config.rs

@@ -200,23 +200,23 @@ struct Build {
     target: Vec<String>,
     cargo: Option<String>,
     rustc: Option<String>,
-    low_priority: Option<bool>,
-    compiler_docs: Option<bool>,
     docs: Option<bool>,
+    compiler_docs: Option<bool>,
     submodules: Option<bool>,
     fast_submodules: Option<bool>,
     gdb: Option<String>,
-    locked_deps: Option<bool>,
-    vendor: Option<bool>,
     nodejs: Option<String>,
     python: Option<String>,
+    locked_deps: Option<bool>,
+    vendor: Option<bool>,
     full_bootstrap: Option<bool>,
     extended: Option<bool>,
     tools: Option<HashSet<String>>,
     verbose: Option<usize>,
     sanitizers: Option<bool>,
     profiler: Option<bool>,
     cargo_native_static: Option<bool>,
+    low_priority: Option<bool>,
     configure_args: Option<Vec<String>>,
     local_rebuild: Option<bool>,
     print_step_timings: Option<bool>,
@@ -228,11 +228,11 @@ struct Build {
 struct Install {
     prefix: Option<String>,
     sysconfdir: Option<String>,
-    datadir: Option<String>,
     docdir: Option<String>,
     bindir: Option<String>,
     libdir: Option<String>,
     mandir: Option<String>,
+    datadir: Option<String>,
 
     // standard paths, currently unused
     infodir: Option<String>,
@@ -243,14 +243,14 @@ struct Install {
 #[derive(Deserialize, Default)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 struct Llvm {
-    ccache: Option<StringOrBool>,
-    ninja: Option<bool>,
-    assertions: Option<bool>,
     optimize: Option<bool>,
     thin_lto: Option<bool>,
     release_debuginfo: Option<bool>,
+    assertions: Option<bool>,
+    ccache: Option<StringOrBool>,
     version_check: Option<bool>,
     static_libstdcpp: Option<bool>,
+    ninja: Option<bool>,
     targets: Option<String>,
     experimental_targets: Option<String>,
     link_jobs: Option<u32>,
@@ -293,6 +293,7 @@ impl Default for StringOrBool {
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 struct Rust {
     optimize: Option<bool>,
+    debug: Option<bool>,
     codegen_units: Option<u32>,
     codegen_units_std: Option<u32>,
     debug_assertions: Option<bool>,
@@ -301,25 +302,24 @@ struct Rust {
     debuginfo_level_std: Option<u32>,
     debuginfo_level_tools: Option<u32>,
     debuginfo_level_tests: Option<u32>,
-    parallel_compiler: Option<bool>,
     backtrace: Option<bool>,
+    incremental: Option<bool>,
+    parallel_compiler: Option<bool>,
     default_linker: Option<String>,
     channel: Option<String>,
     musl_root: Option<String>,
     rpath: Option<bool>,
+    verbose_tests: Option<bool>,
     optimize_tests: Option<bool>,
     codegen_tests: Option<bool>,
     ignore_git: Option<bool>,
-    debug: Option<bool>,
     dist_src: Option<bool>,
-    verbose_tests: Option<bool>,
-    incremental: Option<bool>,
     save_toolstates: Option<String>,
     codegen_backends: Option<Vec<String>>,
     codegen_backends_dir: Option<String>,
     lld: Option<bool>,
-    lldb: Option<bool>,
     llvm_tools: Option<bool>,
+    lldb: Option<bool>,
     deny_warnings: Option<bool>,
     backtrace_on_ice: Option<bool>,
     verify_llvm_ir: Option<bool>,
@@ -333,13 +333,13 @@ struct Rust {
 #[derive(Deserialize, Default)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 struct TomlTarget {
-    llvm_config: Option<String>,
-    llvm_filecheck: Option<String>,
     cc: Option<String>,
     cxx: Option<String>,
     ar: Option<String>,
     ranlib: Option<String>,
     linker: Option<String>,
+    llvm_config: Option<String>,
+    llvm_filecheck: Option<String>,
     android_ndk: Option<String>,
     crt_static: Option<bool>,
     musl_root: Option<String>,