Auto merge of #65495 - Centril:rollup-tguwjt5, r=Centril

Rollup of 8 pull requests

Successful merges:

 - #65237 (Move debug_map assertions after check for err)
 - #65316 (make File::try_clone produce non-inheritable handles on Windows)
 - #65319 (InterpCx: make memory field public)
 - #65461 (Don't recommend ONCE_INIT in std::sync::Once)
 - #65465 (Move syntax::ext to a syntax_expand and refactor some attribute logic)
 - #65475 (add example for type_name)
 - #65478 (fmt::Write is about string slices, not byte slices)
 - #65486 (doc: fix typo in OsStrExt and OsStringExt)

Failed merges:

r? @ghost

4 files changed, 60 insertions, 9 deletions

diff --git a/src/libcore/any.rs b/src/libcore/any.rs
index f75b7a45443..e2704e807d1 100644
--- a/src/libcore/any.rs
+++ b/src/libcore/any.rs
@@ -445,6 +445,15 @@ impl TypeId {
 ///
 /// The current implementation uses the same infrastructure as compiler
 /// diagnostics and debuginfo, but this is not guaranteed.
+///
+/// # Example
+///
+/// ```rust
+/// assert_eq!(
+///     std::any::type_name::<Option<String>>(),
+///     "core::option::Option<alloc::string::String>",
+/// );
+/// ```
 #[stable(feature = "type_name", since = "1.38.0")]
 #[rustc_const_unstable(feature = "const_type_name")]
 pub const fn type_name<T: ?Sized>() -> &'static str {
diff --git a/src/libcore/fmt/builders.rs b/src/libcore/fmt/builders.rs
index 15ce2277fa0..e6e3454b36f 100644
--- a/src/libcore/fmt/builders.rs
+++ b/src/libcore/fmt/builders.rs
@@ -775,10 +775,10 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
                reason = "recently added",
                issue = "62482")]
     pub fn key(&mut self, key: &dyn fmt::Debug) -> &mut DebugMap<'a, 'b> {
-        assert!(!self.has_key, "attempted to begin a new map entry \
-                                without completing the previous one");
-
         self.result = self.result.and_then(|_| {
+            assert!(!self.has_key, "attempted to begin a new map entry \
+                                    without completing the previous one");
+
             if self.is_pretty() {
                 if !self.has_fields {
                     self.fmt.write_str("\n")?;
@@ -839,9 +839,9 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
                reason = "recently added",
                issue = "62482")]
     pub fn value(&mut self, value: &dyn fmt::Debug) -> &mut DebugMap<'a, 'b> {
-        assert!(self.has_key, "attempted to format a map value before its key");
-
         self.result = self.result.and_then(|_| {
+            assert!(self.has_key, "attempted to format a map value before its key");
+
             if self.is_pretty() {
                 let mut slot = None;
                 let mut writer = PadAdapter::wrap(&mut self.fmt, &mut slot, &mut self.state);
@@ -924,9 +924,11 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
     /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn finish(&mut self) -> fmt::Result {
-        assert!(!self.has_key, "attempted to finish a map with a partial entry");
+        self.result.and_then(|_| {
+            assert!(!self.has_key, "attempted to finish a map with a partial entry");
 
-        self.result.and_then(|_| self.fmt.write_str("}"))
+            self.fmt.write_str("}")
+        })
     }
 
     fn is_pretty(&self) -> bool {
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 5dfdd162306..8413b2e0ac4 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -108,10 +108,10 @@ pub struct Error;
 /// [`io::Write`]: ../../std/io/trait.Write.html
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Write {
-    /// Writes a slice of bytes into this writer, returning whether the write
+    /// Writes a string slice into this writer, returning whether the write
     /// succeeded.
     ///
-    /// This method can only succeed if the entire byte slice was successfully
+    /// This method can only succeed if the entire string slice was successfully
     /// written, and this method will not return until all data has been
     /// written or an error occurs.
     ///
diff --git a/src/libcore/tests/fmt/builders.rs b/src/libcore/tests/fmt/builders.rs
index 200659b91bb..25572443281 100644
--- a/src/libcore/tests/fmt/builders.rs
+++ b/src/libcore/tests/fmt/builders.rs
@@ -320,6 +320,46 @@ mod debug_map {
     }
 
     #[test]
+    fn test_entry_err() {
+        // Ensure errors in a map entry don't trigger panics (#65231)
+        use std::fmt::Write;
+
+        struct ErrorFmt;
+
+        impl fmt::Debug for ErrorFmt {
+            fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result {
+                Err(fmt::Error)
+            }
+        }
+
+        struct KeyValue<K, V>(usize, K, V);
+
+        impl<K, V> fmt::Debug for KeyValue<K, V>
+        where
+            K: fmt::Debug,
+            V: fmt::Debug,
+        {
+            fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+                let mut map = fmt.debug_map();
+
+                for _ in 0..self.0 {
+                    map.entry(&self.1, &self.2);
+                }
+
+                map.finish()
+            }
+        }
+
+        let mut buf = String::new();
+
+        assert!(write!(&mut buf, "{:?}", KeyValue(1, ErrorFmt, "bar")).is_err());
+        assert!(write!(&mut buf, "{:?}", KeyValue(1, "foo", ErrorFmt)).is_err());
+
+        assert!(write!(&mut buf, "{:?}", KeyValue(2, ErrorFmt, "bar")).is_err());
+        assert!(write!(&mut buf, "{:?}", KeyValue(2, "foo", ErrorFmt)).is_err());
+    }
+
+    #[test]
     #[should_panic]
     fn test_invalid_key_when_entry_is_incomplete() {
         struct Foo;