Define only a single NonZero type per macro call

Later in this stack, as the nonzero_integers macro is going to be
responsible for producing a larger fraction of the API for the NonZero
integer types, it will need to receive a number of additional arguments
beyond the ones currently seen here.

Additional arguments, especially named arguments across multiple lines,
will turn out clearer if everything in one macro call is for the same
NonZero type.

This commit adopts a similar arrangement to what we do for generating
the API of the integer primitives (`impl u8` etc), which also generate a
single type's API per top-level macro call, rather than generating all
12 impl blocks for the 12 types from one macro call.

Author: dtolnay

library/core/src/num/nonzero.rs

@@ -22,9 +22,10 @@ macro_rules! impl_nonzero_fmt {
     }
 }
 
-macro_rules! nonzero_integers {
-    ( $( #[$stability: meta] #[$const_new_unchecked_stability: meta] $Ty: ident($Int: ty); )+ ) => {
-        $(
+macro_rules! nonzero_integer {
+    (
+        #[$stability:meta] #[$const_new_unchecked_stability:meta] $Ty:ident($Int:ty);
+    ) => {
             /// An integer that is known not to equal zero.
             ///
             /// This enables some memory layout optimization.
@@ -186,8 +187,7 @@ macro_rules! nonzero_integers {
             impl_nonzero_fmt! {
                 #[$stability] (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $Ty
             }
-        )+
-    }
+    };
 }
 
 macro_rules! from_str_radix_nzint_impl {
@@ -1382,17 +1382,50 @@ nonzero_bits! {
     NonZeroIsize(isize);
 }
 
-nonzero_integers! {
+nonzero_integer! {
     #[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU8(u8);
+}
+
+nonzero_integer! {
     #[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU16(u16);
+}
+
+nonzero_integer! {
     #[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU32(u32);
+}
+
+nonzero_integer! {
     #[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU64(u64);
+}
+
+nonzero_integer! {
     #[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU128(u128);
+}
+
+nonzero_integer! {
     #[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroUsize(usize);
+}
+
+nonzero_integer! {
     #[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI8(i8);
+}
+
+nonzero_integer! {
     #[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI16(i16);
+}
+
+nonzero_integer! {
     #[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI32(i32);
+}
+
+nonzero_integer! {
     #[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI64(i64);
+}
+
+nonzero_integer! {
     #[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI128(i128);
+}
+
+nonzero_integer! {
     #[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroIsize(isize);
 }