test that '_ is not linted by single_char_lifetime_names

Author: PatchMixolydic

tests/ui/single_char_lifetime_names.rs

@@ -1,5 +1,6 @@
 #![warn(clippy::single_char_lifetime_names)]
 
+// Lifetimes should only be linted when they're introduced
 struct DiagnosticCtx<'a, 'b>
 where
     'a: 'b,
@@ -8,6 +9,7 @@ where
     _unit: &'b (),
 }
 
+// Only the lifetimes on the `impl`'s generics should be linted
 impl<'a, 'b> DiagnosticCtx<'a, 'b> {
     fn new(source: &'a str, unit: &'b ()) -> DiagnosticCtx<'a, 'b> {
         Self {
@@ -17,6 +19,7 @@ impl<'a, 'b> DiagnosticCtx<'a, 'b> {
     }
 }
 
+// No lifetimes should be linted here
 impl<'src, 'unit> DiagnosticCtx<'src, 'unit> {
     fn new_pass(source: &'src str, unit: &'unit ()) -> DiagnosticCtx<'src, 'unit> {
         Self {
@@ -26,6 +29,13 @@ impl<'src, 'unit> DiagnosticCtx<'src, 'unit> {
     }
 }
 
+// Only 'a should be linted here
+fn split_once<'a>(base: &'a str, other: &'_ str) -> (&'a str, Option<&'a str>) {
+    base.split_once(other)
+        .map(|(left, right)| (left, Some(right)))
+        .unwrap_or((base, None))
+}
+
 fn main() {
     let src = "loop {}";
     let unit = ();

tests/ui/single_char_lifetime_names.stderr

@@ -1,5 +1,5 @@
 error: single-character lifetime names are likely uninformative
-  --> $DIR/single_char_lifetime_names.rs:3:22
+  --> $DIR/single_char_lifetime_names.rs:4:22
    |
 LL | struct DiagnosticCtx<'a, 'b>
    |                      ^^
@@ -8,28 +8,36 @@ LL | struct DiagnosticCtx<'a, 'b>
    = help: use a more informative name
 
 error: single-character lifetime names are likely uninformative
-  --> $DIR/single_char_lifetime_names.rs:3:26
+  --> $DIR/single_char_lifetime_names.rs:4:26
    |
 LL | struct DiagnosticCtx<'a, 'b>
    |                          ^^
    |
    = help: use a more informative name
 
 error: single-character lifetime names are likely uninformative
-  --> $DIR/single_char_lifetime_names.rs:11:6
+  --> $DIR/single_char_lifetime_names.rs:13:6
    |
 LL | impl<'a, 'b> DiagnosticCtx<'a, 'b> {
    |      ^^
    |
    = help: use a more informative name
 
 error: single-character lifetime names are likely uninformative
-  --> $DIR/single_char_lifetime_names.rs:11:10
+  --> $DIR/single_char_lifetime_names.rs:13:10
    |
 LL | impl<'a, 'b> DiagnosticCtx<'a, 'b> {
    |          ^^
    |
    = help: use a more informative name
 
-error: aborting due to 4 previous errors
+error: single-character lifetime names are likely uninformative
+  --> $DIR/single_char_lifetime_names.rs:33:15
+   |
+LL | fn split_once<'a>(base: &'a str, other: &'_ str) -> (&'a str, Option<&'a str>) {
+   |               ^^
+   |
+   = help: use a more informative name
+
+error: aborting due to 5 previous errors