Rework the suspicious formatting lints.

Author: Jarcho

clippy_lints/src/formatting.rs

@@ -1346,6 +1346,10 @@ pub trait StrExt {
     where
         P: Pattern,
         for<'a> P::Searcher<'a>: ReverseSearcher<'a>;
+
+    /// Splits a string into a prefix and everything proceeding it. Returns `None` if the string
+    /// doesn't start with the prefix.
+    fn split_multipart_prefix(&self, pats: impl IntoIterator<Item: Pattern>) -> Option<[&Self; 2]>;
 }
 impl StrExt for str {
     fn find_bounded_inclusive(&self, pat: impl Pattern) -> Option<&Self> {
@@ -1387,6 +1391,16 @@ impl StrExt for str {
     {
         self.strip_suffix(pat).map(|rest| [rest, &self[rest.len()..]])
     }
+
+    /// Splits a string into a prefix and everything proceeding it. Returns `None` if the string
+    /// doesn't start with the prefix.
+    fn split_multipart_prefix(&self, pats: impl IntoIterator<Item: Pattern>) -> Option<[&Self; 2]> {
+        let mut s = self;
+        for pat in pats {
+            s = s.strip_prefix(pat)?;
+        }
+        Some([&self[..self.len() - s.len()], s])
+    }
 }
 
 /// Checks if the last token of the string is either a line comment or an incomplete token.

clippy_utils/src/source.rs

@@ -0,0 +1,74 @@
+//@aux-build:../auxiliary/proc_macros.rs
+#![deny(clippy::possible_missing_comma)]
+
+use proc_macros::{external, inline_macros, with_span};
+
+#[rustfmt::skip]
+#[inline_macros]
+fn main() {
+    {
+        let x = 20;
+        let y = &32;
+
+        let _ = [1, 2, *y]; //~ possible_missing_comma
+        let _ = [1, 2, -x]; //~ possible_missing_comma
+        let _ = [1, x - 2, -x]; //~ possible_missing_comma
+        let _ = [1, 2, -x - 2]; //~ possible_missing_comma
+        let _ = [1, 2 * x * 2, -x]; //~ possible_missing_comma
+
+        let _ = [
+            1,
+            x,
+            -2 * x * 2, //~ possible_missing_comma
+            -x, //~ possible_missing_comma
+        ];
+
+        let _ = (1, &x); //~ possible_missing_comma
+        let _ = (1, x, -1); //~ possible_missing_comma
+
+        let _ = (1-x);
+        let _ = (1- x);
+        let _ = (1 -/* comment */x);
+        let _ = (1, 2*y - 5);
+        let _ = (1, 2 /x);
+        let _ = (1, 2 <x);
+        let _ = (1, 2 !=x);
+        let _ = (1, 2 |x);
+        let _ = (1, 2 <<x);
+
+        let _ = [
+            1
+            - x,
+            x
+            * y,
+        ];
+    }
+
+    {
+        let x = true;
+        let y = false;
+
+        let _ = (y, &&x); //~ possible_missing_comma
+        let _ = (y && x);
+        let _ = (y&&x);
+    }
+
+    with_span! {
+        span
+        let x = 0;
+        let _ = (x -1);
+    }
+
+    external! {
+        let x = 0;
+        let _ = (x -1);
+    }
+
+    inline! {
+        let x = 0;
+        let _ = (x, -1); //~ possible_missing_comma
+        let _ = (x, -$(@tt 1)); //~ possible_missing_comma
+        let _ = ($(@expr x -1));
+        let _ = (x $(@tt -)1);
+    }
+}

tests/ui/formatting.rs

@@ -0,0 +1,74 @@
+//@aux-build:../auxiliary/proc_macros.rs
+#![deny(clippy::possible_missing_comma)]
+
+use proc_macros::{external, inline_macros, with_span};
+
+#[rustfmt::skip]
+#[inline_macros]
+fn main() {
+    {
+        let x = 20;
+        let y = &32;
+
+        let _ = [1, 2 * y]; //~ possible_missing_comma
+        let _ = [1, 2 - x]; //~ possible_missing_comma
+        let _ = [1, x - 2 - x]; //~ possible_missing_comma
+        let _ = [1, 2 - x - 2]; //~ possible_missing_comma
+        let _ = [1, 2 * x * 2 - x]; //~ possible_missing_comma
+
+        let _ = [
+            1,
+            x
+            - 2 * x * 2 //~ possible_missing_comma
+            - x, //~ possible_missing_comma
+        ];
+
+        let _ = (1 & x); //~ possible_missing_comma
+        let _ = (1, x - 1); //~ possible_missing_comma
+
+        let _ = (1-x);
+        let _ = (1- x);
+        let _ = (1 -/* comment */x);
+        let _ = (1, 2*y - 5);
+        let _ = (1, 2 /x);
+        let _ = (1, 2 <x);
+        let _ = (1, 2 !=x);
+        let _ = (1, 2 |x);
+        let _ = (1, 2 <<x);
+
+        let _ = [
+            1
+            - x,
+            x
+            * y,
+        ];
+    }
+
+    {
+        let x = true;
+        let y = false;
+
+        let _ = (y && x); //~ possible_missing_comma
+        let _ = (y && x);
+        let _ = (y&&x);
+    }
+
+    with_span! {
+        span
+        let x = 0;
+        let _ = (x -1);
+    }
+
+    external! {
+        let x = 0;
+        let _ = (x -1);
+    }
+
+    inline! {
+        let x = 0;
+        let _ = (x - 1); //~ possible_missing_comma
+        let _ = (x - $(@tt 1)); //~ possible_missing_comma
+        let _ = ($(@expr x -1));
+        let _ = (x $(@tt -)1);
+    }
+}

tests/ui/formatting.stderr

@@ -0,0 +1,74 @@
+//@aux-build:../auxiliary/proc_macros.rs
+#![deny(clippy::possible_missing_comma)]
+
+use proc_macros::{external, inline_macros, with_span};
+
+#[rustfmt::skip]
+#[inline_macros]
+fn main() {
+    {
+        let x = 20;
+        let y = &32;
+
+        let _ = [1, 2 *y]; //~ possible_missing_comma
+        let _ = [1, 2 -x]; //~ possible_missing_comma
+        let _ = [1, x - 2 -x]; //~ possible_missing_comma
+        let _ = [1, 2 -x - 2]; //~ possible_missing_comma
+        let _ = [1, 2 * x * 2 -x]; //~ possible_missing_comma
+
+        let _ = [
+            1,
+            x
+            -2 * x * 2 //~ possible_missing_comma
+            -x, //~ possible_missing_comma
+        ];
+
+        let _ = (1 &x); //~ possible_missing_comma
+        let _ = (1, x -1); //~ possible_missing_comma
+
+        let _ = (1-x);
+        let _ = (1- x);
+        let _ = (1 -/* comment */x);
+        let _ = (1, 2*y - 5);
+        let _ = (1, 2 /x);
+        let _ = (1, 2 <x);
+        let _ = (1, 2 !=x);
+        let _ = (1, 2 |x);
+        let _ = (1, 2 <<x);
+
+        let _ = [
+            1
+            - x,
+            x
+            * y,
+        ];
+    }
+
+    {
+        let x = true;
+        let y = false;
+
+        let _ = (y &&x); //~ possible_missing_comma
+        let _ = (y && x);
+        let _ = (y&&x);
+    }
+
+    with_span! {
+        span
+        let x = 0;
+        let _ = (x -1);
+    }
+
+    external! {
+        let x = 0;
+        let _ = (x -1);
+    }
+
+    inline! {
+        let x = 0;
+        let _ = (x -1); //~ possible_missing_comma
+        let _ = (x -$(@tt 1)); //~ possible_missing_comma
+        let _ = ($(@expr x -1));
+        let _ = (x $(@tt -)1);
+    }
+}