From 1b587a6e76200fdd8364ef910246efa11c973e7b Mon Sep 17 00:00:00 2001
From: Michael Howell <michael@notriddle.com>
Date: Tue, 6 Aug 2024 14:33:14 -0700
Subject: alloc: add ToString specialization for `&&str`

Fixes #128690
---
 library/alloc/src/string.rs | 43 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 35 insertions(+), 8 deletions(-)

(limited to 'library/alloc/src')

diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index 124230812df..d943901e9ec 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -2643,14 +2643,41 @@ impl ToString for i8 {
     }
 }
 
-#[doc(hidden)]
-#[cfg(not(no_global_oom_handling))]
-#[stable(feature = "str_to_string_specialization", since = "1.9.0")]
-impl ToString for str {
-    #[inline]
-    fn to_string(&self) -> String {
-        String::from(self)
-    }
+// Generic/generated code can sometimes have multiple, nested references
+// for strings, including `&&&str`s that would never be written
+// by hand. This macro generates twelve layers of nested `&`-impl
+// for primitive strings.
+macro_rules! to_string_str {
+    {type ; x $($x:ident)*} => {
+        &to_string_str! { type ; $($x)* }
+    };
+    {type ;} => { str };
+    {impl ; x $($x:ident)*} => {
+        to_string_str! { $($x)* }
+    };
+    {impl ;} => { };
+    {$self:expr ; x $($x:ident)*} => {
+        *(to_string_str! { $self ; $($x)* })
+    };
+    {$self:expr ;} => { $self };
+    {$($x:ident)*} => {
+        #[doc(hidden)]
+        #[cfg(not(no_global_oom_handling))]
+        #[stable(feature = "str_to_string_specialization", since = "1.9.0")]
+        impl ToString for to_string_str!(type ; $($x)*) {
+            #[inline]
+            fn to_string(&self) -> String {
+                String::from(to_string_str!(self ; $($x)*))
+            }
+        }
+        to_string_str! { impl ; $($x)* }
+    };
+}
+
+to_string_str! {
+    x x x x
+    x x x x
+    x x x x
 }
 
 #[doc(hidden)]
-- 
cgit 1.4.1-3-g733a5


From 3312f5d65244b4ccb035be7b4c61541afc211914 Mon Sep 17 00:00:00 2001
From: Michael Howell <michael@notriddle.com>
Date: Wed, 7 Aug 2024 09:06:49 -0700
Subject: alloc: make `to_string_str!` a bit less complex

---
 library/alloc/src/string.rs | 57 ++++++++++++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 22 deletions(-)

(limited to 'library/alloc/src')

diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index d943901e9ec..e628be1546f 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -2647,37 +2647,50 @@ impl ToString for i8 {
 // for strings, including `&&&str`s that would never be written
 // by hand. This macro generates twelve layers of nested `&`-impl
 // for primitive strings.
-macro_rules! to_string_str {
-    {type ; x $($x:ident)*} => {
-        &to_string_str! { type ; $($x)* }
-    };
-    {type ;} => { str };
-    {impl ; x $($x:ident)*} => {
-        to_string_str! { $($x)* }
+#[cfg(not(no_global_oom_handling))]
+macro_rules! to_string_str_wrap_in_ref {
+    {x $($x:ident)*} => {
+        &to_string_str_wrap_in_ref! { $($x)* }
     };
-    {impl ;} => { };
+    {} => { str };
+}
+#[cfg(not(no_global_oom_handling))]
+macro_rules! to_string_expr_wrap_in_deref {
     {$self:expr ; x $($x:ident)*} => {
-        *(to_string_str! { $self ; $($x)* })
+        *(to_string_expr_wrap_in_deref! { $self ; $($x)* })
     };
     {$self:expr ;} => { $self };
-    {$($x:ident)*} => {
-        #[doc(hidden)]
-        #[cfg(not(no_global_oom_handling))]
-        #[stable(feature = "str_to_string_specialization", since = "1.9.0")]
-        impl ToString for to_string_str!(type ; $($x)*) {
-            #[inline]
-            fn to_string(&self) -> String {
-                String::from(to_string_str!(self ; $($x)*))
+}
+#[cfg(not(no_global_oom_handling))]
+macro_rules! to_string_str {
+    {$($($x:ident)*),+} => {
+        $(
+            #[doc(hidden)]
+            #[stable(feature = "str_to_string_specialization", since = "1.9.0")]
+            impl ToString for to_string_str_wrap_in_ref!($($x)*) {
+                #[inline]
+                fn to_string(&self) -> String {
+                    String::from(to_string_expr_wrap_in_deref!(self ; $($x)*))
+                }
             }
-        }
-        to_string_str! { impl ; $($x)* }
+        )+
     };
 }
 
+#[cfg(not(no_global_oom_handling))]
 to_string_str! {
-    x x x x
-    x x x x
-    x x x x
+    x x x x x x x x x x x x,
+    x x x x x x x x x x x,
+    x x x x x x x x x x,
+    x x x x x x x x x,
+    x x x x x x x x,
+    x x x x x x x,
+    x x x x x x,
+    x x x x x,
+    x x x x,
+    x x x,
+    x x,
+    x,
 }
 
 #[doc(hidden)]
-- 
cgit 1.4.1-3-g733a5


From 027b19fa9b85c3330d2eb38970c22e44873db2fc Mon Sep 17 00:00:00 2001
From: schvv31n <tim.kurdov@gmail.com>
Date: Mon, 12 Aug 2024 18:32:31 +0100
Subject: std::fmt::FormatterFn -> std::fmt::FromFn

---
 library/alloc/src/fmt.rs         |  2 +-
 library/core/src/fmt/builders.rs | 19 ++++++++++++++-----
 library/core/src/fmt/mod.rs      |  2 +-
 3 files changed, 16 insertions(+), 7 deletions(-)

(limited to 'library/alloc/src')

diff --git a/library/alloc/src/fmt.rs b/library/alloc/src/fmt.rs
index 4b9b90fc1f1..571fcd177aa 100644
--- a/library/alloc/src/fmt.rs
+++ b/library/alloc/src/fmt.rs
@@ -581,7 +581,7 @@ pub use core::fmt::Alignment;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::fmt::Error;
 #[unstable(feature = "debug_closure_helpers", issue = "117729")]
-pub use core::fmt::FormatterFn;
+pub use core::fmt::{from_fn, FromFn};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::fmt::{write, Arguments};
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/core/src/fmt/builders.rs b/library/core/src/fmt/builders.rs
index 794ca1851b1..467fa17a6f3 100644
--- a/library/core/src/fmt/builders.rs
+++ b/library/core/src/fmt/builders.rs
@@ -1018,7 +1018,8 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
     }
 }
 
-/// Implements [`fmt::Debug`] and [`fmt::Display`] using a function.
+/// Creates a type whose [`fmt::Debug`] and [`fmt::Display`] impls are provided with the function
+/// `f`.
 ///
 /// # Examples
 ///
@@ -1030,17 +1031,25 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
 /// assert_eq!(format!("{}", value), "a");
 /// assert_eq!(format!("{:?}", value), "'a'");
 ///
-/// let wrapped = fmt::FormatterFn(|f| write!(f, "{value:?}"));
+/// let wrapped = fmt::from_fn(|f| write!(f, "{value:?}"));
 /// assert_eq!(format!("{}", wrapped), "'a'");
 /// assert_eq!(format!("{:?}", wrapped), "'a'");
 /// ```
 #[unstable(feature = "debug_closure_helpers", issue = "117729")]
-pub struct FormatterFn<F>(pub F)
+pub fn from_fn<F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result>(f: F) -> FromFn<F> {
+    FromFn(f)
+}
+
+/// Implements [`fmt::Debug`] and [`fmt::Display`] using a function.
+///
+/// Created with [`from_fn`].
+#[unstable(feature = "debug_closure_helpers", issue = "117729")]
+pub struct FromFn<F>(F)
 where
     F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result;
 
 #[unstable(feature = "debug_closure_helpers", issue = "117729")]
-impl<F> fmt::Debug for FormatterFn<F>
+impl<F> fmt::Debug for FromFn<F>
 where
     F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result,
 {
@@ -1050,7 +1059,7 @@ where
 }
 
 #[unstable(feature = "debug_closure_helpers", issue = "117729")]
-impl<F> fmt::Display for FormatterFn<F>
+impl<F> fmt::Display for FromFn<F>
 where
     F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result,
 {
diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index 60c0dc76852..485ad4aee19 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -34,7 +34,7 @@ pub enum Alignment {
 }
 
 #[unstable(feature = "debug_closure_helpers", issue = "117729")]
-pub use self::builders::FormatterFn;
+pub use self::builders::{from_fn, FromFn};
 #[stable(feature = "debug_builders", since = "1.2.0")]
 pub use self::builders::{DebugList, DebugMap, DebugSet, DebugStruct, DebugTuple};
 
-- 
cgit 1.4.1-3-g733a5