[OTHER] Inconsistent #[inline] attributes in ToLexical-like and FromLexical-like methods.

[zheland]

Description

In general, there is some inconsistency in attributes in ToLexical-like and FromLexical-like implementations.
For example unsigned ints ToLexial implementations lack #[inline] attributes so they do not inlined across crates, while implementations for signed ints have these attributes.

This problem could probably be considered a bug.

Currently

macro	trait	inline attr	$(#[$meta:meta])?
unsigned_to_lexical	ToLexical	no	yes
unsigned_to_lexical	ToLexicalWithOptions	no	yes
signed_to_lexical	ToLexical	#[inline]	yes
signed_to_lexical	ToLexicalWithOptions	#[inline]	duplicated
float_to_lexical	ToLexical	no	yes
float_to_lexical	ToLexicalWithOptions	no	yes
integer_from_lexical	FromLexical	#[cfg_attr(not(feature = "compact"), inline)]	yes
integer_from_lexical	FromLexicalWithOptions	#[cfg_attr(not(feature = "compact"), inline)]	yes
float_from_lexical	FromLexical	#[cfg_attr(not(feature = "compact"), inline)]	no
float_from_lexical	FromLexicalWithOptions	#[cfg_attr(not(feature = "compact"), inline)]	no

Expected

Either:

• Same attributes for all implementations, probably: #[cfg_attr(not(feature = "compact"), inline)].
• #[cfg_attr(not(feature = "compact"), inline)] for FromLexical-like and #[inline] for ToLexical-like.
• Or the comments with the explanation for the inconsistency between attributes

Additionally

$(#[$meta:meta])? are not longer used. Maybe it is better to remove it as well instead of adding where it is missed?

Example diff

Example with all ToLexical and FromLexical methods using #[cfg_attr(not(feature = "compact"), inline)] and with $(#[$meta:meta])? removed.

diff --git a/lexical-parse-integer/src/api.rs b/lexical-parse-integer/src/api.rs
index 9240212..5cc08eb 100644
--- a/lexical-parse-integer/src/api.rs
+++ b/lexical-parse-integer/src/api.rs
@@ -17,5 +17,4 @@ use crate::parse::ParseInteger;
 macro_rules! integer_from_lexical {
-    ($($t:ident $unsigned:ident $(, #[$meta:meta])? ; )*) => ($(
+    ($($t:ident $unsigned:ident ; )*) => ($(
         impl FromLexical for $t {
-            $(#[$meta:meta])?
             #[cfg_attr(not(feature = "compact"), inline)]
@@ -26,3 +25,2 @@ macro_rules! integer_from_lexical {
 
-            $(#[$meta:meta])?
             #[cfg_attr(not(feature = "compact"), inline)]
@@ -39,3 +37,2 @@ macro_rules! integer_from_lexical {
 
-            $(#[$meta:meta])?
             #[cfg_attr(not(feature = "compact"), inline)]
@@ -53,3 +50,2 @@ macro_rules! integer_from_lexical {
 
-            $(#[$meta:meta])?
             #[cfg_attr(not(feature = "compact"), inline)]
diff --git a/lexical-write-float/src/api.rs b/lexical-write-float/src/api.rs
index 76c3356..f583618 100644
--- a/lexical-write-float/src/api.rs
+++ b/lexical-write-float/src/api.rs
@@ -20,5 +20,5 @@ const DEFAULT_OPTIONS: Options = Options::new();
 macro_rules! float_to_lexical {
-    ($($t:tt $(, #[$meta:meta])? ; )*) => ($(
+    ($($t:tt ; )*) => ($(
         impl ToLexical for $t {
-            $(#[$meta:meta])?
+            #[cfg_attr(not(feature = "compact"), inline)]
             fn to_lexical(self, bytes: &mut [u8])
@@ -33,3 +33,3 @@ macro_rules! float_to_lexical {
             type Options = Options;
-            $(#[$meta:meta])?
+            #[cfg_attr(not(feature = "compact"), inline)]
             fn to_lexical_with_options<'a, const FORMAT: u128>(
diff --git a/lexical-write-integer/src/api.rs b/lexical-write-integer/src/api.rs
index 5cc7f50..11d34d1 100644
--- a/lexical-write-integer/src/api.rs
+++ b/lexical-write-integer/src/api.rs
@@ -76,5 +76,5 @@ where
 macro_rules! unsigned_to_lexical {
-    ($($narrow:tt $wide:tt $(, #[$meta:meta])? ; )*) => ($(
+    ($($narrow:tt $wide:tt ; )*) => ($(
         impl ToLexical for $narrow {
-            $(#[$meta:meta])?
+            #[cfg_attr(not(feature = "compact"), inline)]
             fn to_lexical(self, bytes: &mut [u8])
@@ -90,3 +90,3 @@ macro_rules! unsigned_to_lexical {
 
-            $(#[$meta:meta])?
+            #[cfg_attr(not(feature = "compact"), inline)]
             fn to_lexical_with_options<'a, const FORMAT: u128>(
@@ -124,7 +124,5 @@ unsigned_to_lexical! { usize u64 ; }
 macro_rules! signed_to_lexical {
-    ($($narrow:tt $wide:tt $unsigned:tt $(, #[$meta:meta])? ; )*) => ($(
+    ($($narrow:tt $wide:tt $unsigned:tt ; )*) => ($(
         impl ToLexical for $narrow {
-            $(#[$meta:meta])?
-            $(#[$meta:meta])?
-            #[inline]
+            #[cfg_attr(not(feature = "compact"), inline)]
             fn to_lexical(self, bytes: &mut [u8])
@@ -139,4 +137,3 @@ macro_rules! signed_to_lexical {
             type Options = Options;
-            $(#[$meta:meta])?
-            #[inline]
+            #[cfg_attr(not(feature = "compact"), inline)]
             fn to_lexical_with_options<'a, const FORMAT: u128>(

[Alexhuszagh]

This was likely introduced with the formatting API which added like many, many different layers of abstraction that needed to be removed at compilation when not used, causing inconsistency with inlining. Ideally, there should be soft inlining, at best, at API boundaries and only have the inlining internally within the crate.

[Alexhuszagh]

I submitted a PR @zheland but this is all your work so if you'd like to submit it I'd be more than happy to close mine and accept it. All this lgtm. Thank you for this.

[zheland]

Uh, okay, done :-) #151

I also checked other pub functions and methods with clippy lint missing_inline_in_public_items and haven't find any other missing inline for publicly visible functions.