improve non_snake_case diagnostics

Use a structured suggestion and tighten the span to just the identifier.

src/test/ui/enable-unstable-lib-feature.stderr

@@ -1,8 +1,8 @@
-error: function `BOGUS` should have a snake case name such as `bogus`
-  --> $DIR/enable-unstable-lib-feature.rs:12:1
+error: function `BOGUS` should have a snake case name
+  --> $DIR/enable-unstable-lib-feature.rs:12:8
    |
 LL | pub fn BOGUS() { } //~ ERROR
-   | ^^^^^^^^^^^^^^^^^^
+   |        ^^^^^ help: convert the identifier to snake case: `bogus`
    |
 note: lint level defined here
   --> $DIR/enable-unstable-lib-feature.rs:6:9

src/test/ui/expr_attr_paren_order.stderr

@@ -1,8 +1,8 @@
-error: variable `X` should have a snake case name such as `x`
+error: variable `X` should have a snake case name
   --> $DIR/expr_attr_paren_order.rs:19:17
    |
 LL |             let X = 0; //~ ERROR snake case name
-   |                 ^
+   |                 ^ help: convert the identifier to snake case: `x`
    |
 note: lint level defined here
   --> $DIR/expr_attr_paren_order.rs:17:17

src/test/ui/lint/command-line-lint-group-deny.stderr

@@ -1,8 +1,8 @@
-error: variable `_InappropriateCamelCasing` should have a snake case name such as `_inappropriate_camel_casing`
+error: variable `_InappropriateCamelCasing` should have a snake case name
   --> $DIR/command-line-lint-group-deny.rs:4:9
    |
 LL |     let _InappropriateCamelCasing = true; //~ ERROR should have a snake
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `_inappropriate_camel_casing`
    |
    = note: `-D non-snake-case` implied by `-D bad-style`
 

src/test/ui/lint/command-line-lint-group-forbid.stderr

@@ -1,8 +1,8 @@
-error: variable `_InappropriateCamelCasing` should have a snake case name such as `_inappropriate_camel_casing`
+error: variable `_InappropriateCamelCasing` should have a snake case name
   --> $DIR/command-line-lint-group-forbid.rs:4:9
    |
 LL |     let _InappropriateCamelCasing = true; //~ ERROR should have a snake
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `_inappropriate_camel_casing`
    |
    = note: `-F non-snake-case` implied by `-F bad-style`
 

src/test/ui/lint/command-line-lint-group-warn.stderr

@@ -1,8 +1,8 @@
-warning: variable `_InappropriateCamelCasing` should have a snake case name such as `_inappropriate_camel_casing`
+warning: variable `_InappropriateCamelCasing` should have a snake case name
   --> $DIR/command-line-lint-group-warn.rs:5:9
    |
 LL |     let _InappropriateCamelCasing = true;
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `_inappropriate_camel_casing`
    |
    = note: `-W non-snake-case` implied by `-W bad-style`
 

src/test/ui/lint/lint-group-nonstandard-style.stderr

@@ -11,11 +11,11 @@ LL |         #![warn(nonstandard_style)]
    |                 ^^^^^^^^^^^^^^^^^
    = note: #[warn(non_camel_case_types)] implied by #[warn(nonstandard_style)]
 
-error: function `CamelCase` should have a snake case name such as `camel_case`
-  --> $DIR/lint-group-nonstandard-style.rs:4:1
+error: function `CamelCase` should have a snake case name
+  --> $DIR/lint-group-nonstandard-style.rs:4:4
    |
 LL | fn CamelCase() {} //~ ERROR should have a snake
-   | ^^^^^^^^^^^^^^^^^
+   |    ^^^^^^^^^ help: convert the identifier to snake case: `camel_case`
    |
 note: lint level defined here
   --> $DIR/lint-group-nonstandard-style.rs:1:9
@@ -24,11 +24,11 @@ LL | #![deny(nonstandard_style)]
    |         ^^^^^^^^^^^^^^^^^
    = note: #[deny(non_snake_case)] implied by #[deny(nonstandard_style)]
 
-error: function `CamelCase` should have a snake case name such as `camel_case`
-  --> $DIR/lint-group-nonstandard-style.rs:12:9
+error: function `CamelCase` should have a snake case name
+  --> $DIR/lint-group-nonstandard-style.rs:12:12
    |
 LL |         fn CamelCase() {} //~ ERROR should have a snake
-   |         ^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^ help: convert the identifier to snake case: `camel_case`
    |
 note: lint level defined here
   --> $DIR/lint-group-nonstandard-style.rs:10:14
@@ -50,11 +50,11 @@ LL |     #[forbid(nonstandard_style)]
    |              ^^^^^^^^^^^^^^^^^
    = note: #[forbid(non_upper_case_globals)] implied by #[forbid(nonstandard_style)]
 
-warning: function `CamelCase` should have a snake case name such as `camel_case`
-  --> $DIR/lint-group-nonstandard-style.rs:20:9
+warning: function `CamelCase` should have a snake case name
+  --> $DIR/lint-group-nonstandard-style.rs:20:12
    |
 LL |         fn CamelCase() {} //~ WARN should have a snake
-   |         ^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^ help: convert the identifier to snake case: `camel_case`
    |
 note: lint level defined here
   --> $DIR/lint-group-nonstandard-style.rs:18:17

src/test/ui/lint/lint-non-snake-case-crate-2.rs

@@ -1,5 +1,5 @@
 // compile-flags: --crate-name NonSnakeCase
-// error-pattern: crate `NonSnakeCase` should have a snake case name such as `non_snake_case`
+// error-pattern: crate `NonSnakeCase` should have a snake case name
 
 #![deny(non_snake_case)]
 

src/test/ui/lint/lint-non-snake-case-crate-2.stderr

@@ -1,10 +1,11 @@
-error: crate `NonSnakeCase` should have a snake case name such as `non_snake_case`
+error: crate `NonSnakeCase` should have a snake case name
    |
 note: lint level defined here
   --> $DIR/lint-non-snake-case-crate-2.rs:4:9
    |
 LL | #![deny(non_snake_case)]
    |         ^^^^^^^^^^^^^^
+   = help: convert the identifier to snake case: `non_snake_case`
 
 error: aborting due to previous error
 

src/test/ui/lint/lint-non-snake-case-crate.rs

@@ -1,5 +1,5 @@
 #![crate_name = "NonSnakeCase"]
-//~^ ERROR crate `NonSnakeCase` should have a snake case name such as `non_snake_case`
+//~^ ERROR crate `NonSnakeCase` should have a snake case name
 #![deny(non_snake_case)]
 
 fn main() {}

src/test/ui/lint/lint-non-snake-case-crate.stderr

@@ -1,8 +1,8 @@
-error: crate `NonSnakeCase` should have a snake case name such as `non_snake_case`
-  --> $DIR/lint-non-snake-case-crate.rs:1:1
+error: crate `NonSnakeCase` should have a snake case name
+  --> $DIR/lint-non-snake-case-crate.rs:1:18
    |
 LL | #![crate_name = "NonSnakeCase"]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^ help: convert the identifier to snake case: `non_snake_case`
    |
 note: lint level defined here
   --> $DIR/lint-non-snake-case-crate.rs:3:9

src/test/ui/lint/lint-non-snake-case-functions.rs

@@ -5,28 +5,28 @@ struct Foo;
 
 impl Foo {
     fn Foo_Method() {}
-    //~^ ERROR method `Foo_Method` should have a snake case name such as `foo_method`
+    //~^ ERROR method `Foo_Method` should have a snake case name
 
     // Don't allow two underscores in a row
     fn foo__method(&self) {}
-    //~^ ERROR method `foo__method` should have a snake case name such as `foo_method`
+    //~^ ERROR method `foo__method` should have a snake case name
 
     pub fn xyZ(&mut self) {}
-    //~^ ERROR method `xyZ` should have a snake case name such as `xy_z`
+    //~^ ERROR method `xyZ` should have a snake case name
 
     fn render_HTML() {}
-    //~^ ERROR method `render_HTML` should have a snake case name such as `render_html`
+    //~^ ERROR method `render_HTML` should have a snake case name
 }
 
 trait X {
     fn ABC();
-    //~^ ERROR trait method `ABC` should have a snake case name such as `abc`
+    //~^ ERROR trait method `ABC` should have a snake case name
 
     fn a_b_C(&self) {}
-    //~^ ERROR trait method `a_b_C` should have a snake case name such as `a_b_c`
+    //~^ ERROR trait method `a_b_C` should have a snake case name
 
     fn something__else(&mut self);
-    //~^ ERROR trait method `something__else` should have a snake case name such as `something_else`
+    //~^ ERROR trait method `something__else` should have a snake case name
 }
 
 impl X for Foo {
@@ -36,9 +36,9 @@ impl X for Foo {
 }
 
 fn Cookie() {}
-//~^ ERROR function `Cookie` should have a snake case name such as `cookie`
+//~^ ERROR function `Cookie` should have a snake case name
 
 pub fn bi_S_Cuit() {}
-//~^ ERROR function `bi_S_Cuit` should have a snake case name such as `bi_s_cuit`
+//~^ ERROR function `bi_S_Cuit` should have a snake case name
 
 fn main() { }

src/test/ui/lint/lint-non-snake-case-functions.stderr

@@ -1,8 +1,8 @@
-error: method `Foo_Method` should have a snake case name such as `foo_method`
-  --> $DIR/lint-non-snake-case-functions.rs:7:5
+error: method `Foo_Method` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:7:8
    |
 LL |     fn Foo_Method() {}
-   |     ^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^ help: convert the identifier to snake case: `foo_method`
    |
 note: lint level defined here
   --> $DIR/lint-non-snake-case-functions.rs:1:9
@@ -10,53 +10,53 @@ note: lint level defined here
 LL | #![deny(non_snake_case)]
    |         ^^^^^^^^^^^^^^
 
-error: method `foo__method` should have a snake case name such as `foo_method`
-  --> $DIR/lint-non-snake-case-functions.rs:11:5
+error: method `foo__method` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:11:8
    |
 LL |     fn foo__method(&self) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^ help: convert the identifier to snake case: `foo_method`
 
-error: method `xyZ` should have a snake case name such as `xy_z`
-  --> $DIR/lint-non-snake-case-functions.rs:14:5
+error: method `xyZ` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:14:12
    |
 LL |     pub fn xyZ(&mut self) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^ help: convert the identifier to snake case: `xy_z`
 
-error: method `render_HTML` should have a snake case name such as `render_html`
-  --> $DIR/lint-non-snake-case-functions.rs:17:5
+error: method `render_HTML` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:17:8
    |
 LL |     fn render_HTML() {}
-   |     ^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^ help: convert the identifier to snake case: `render_html`
 
-error: trait method `ABC` should have a snake case name such as `abc`
-  --> $DIR/lint-non-snake-case-functions.rs:22:5
+error: trait method `ABC` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:22:8
    |
 LL |     fn ABC();
-   |     ^^^^^^^^^
+   |        ^^^ help: convert the identifier to snake case: `abc`
 
-error: trait method `a_b_C` should have a snake case name such as `a_b_c`
-  --> $DIR/lint-non-snake-case-functions.rs:25:5
+error: trait method `a_b_C` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:25:8
    |
 LL |     fn a_b_C(&self) {}
-   |     ^^^^^^^^^^^^^^^^^^
+   |        ^^^^^ help: convert the identifier to snake case: `a_b_c`
 
-error: trait method `something__else` should have a snake case name such as `something_else`
-  --> $DIR/lint-non-snake-case-functions.rs:28:5
+error: trait method `something__else` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:28:8
    |
 LL |     fn something__else(&mut self);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `something_else`
 
-error: function `Cookie` should have a snake case name such as `cookie`
-  --> $DIR/lint-non-snake-case-functions.rs:38:1
+error: function `Cookie` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:38:4
    |
 LL | fn Cookie() {}
-   | ^^^^^^^^^^^^^^
+   |    ^^^^^^ help: convert the identifier to snake case: `cookie`
 
-error: function `bi_S_Cuit` should have a snake case name such as `bi_s_cuit`
-  --> $DIR/lint-non-snake-case-functions.rs:41:1
+error: function `bi_S_Cuit` should have a snake case name
+  --> $DIR/lint-non-snake-case-functions.rs:41:8
    |
 LL | pub fn bi_S_Cuit() {}
-   | ^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^ help: convert the identifier to snake case: `bi_s_cuit`
 
 error: aborting due to 9 previous errors
 

src/test/ui/lint/lint-non-snake-case-lifetimes.rs

@@ -1,7 +1,7 @@
 #![deny(non_snake_case)]
 #![allow(dead_code)]
 
-fn f<'FooBar>( //~ ERROR lifetime `'FooBar` should have a snake case name such as `'foo_bar`
+fn f<'FooBar>( //~ ERROR lifetime `'FooBar` should have a snake case name
     _: &'FooBar ()
 ) {}
 

src/test/ui/lint/lint-non-snake-case-lifetimes.stderr

@@ -1,8 +1,8 @@
-error: lifetime `'FooBar` should have a snake case name such as `'foo_bar`
+error: lifetime `'FooBar` should have a snake case name
   --> $DIR/lint-non-snake-case-lifetimes.rs:4:6
    |
-LL | fn f<'FooBar>( //~ ERROR lifetime `'FooBar` should have a snake case name such as `'foo_bar`
-   |      ^^^^^^^
+LL | fn f<'FooBar>( //~ ERROR lifetime `'FooBar` should have a snake case name
+   |      ^^^^^^^ help: convert the identifier to snake case: `'foo_bar`
    |
 note: lint level defined here
   --> $DIR/lint-non-snake-case-lifetimes.rs:1:9

src/test/ui/lint/lint-non-snake-case-modules.rs

@@ -1,7 +1,7 @@
 #![deny(non_snake_case)]
 #![allow(dead_code)]
 
-mod FooBar { //~ ERROR module `FooBar` should have a snake case name such as `foo_bar`
+mod FooBar { //~ ERROR module `FooBar` should have a snake case name
     pub struct S;
 }
 

src/test/ui/lint/lint-non-snake-case-modules.stderr

@@ -1,10 +1,8 @@
-error: module `FooBar` should have a snake case name such as `foo_bar`
-  --> $DIR/lint-non-snake-case-modules.rs:4:1
+error: module `FooBar` should have a snake case name
+  --> $DIR/lint-non-snake-case-modules.rs:4:5
    |
-LL | / mod FooBar { //~ ERROR module `FooBar` should have a snake case name such as `foo_bar`
-LL | |     pub struct S;
-LL | | }
-   | |_^
+LL | mod FooBar { //~ ERROR module `FooBar` should have a snake case name
+   |     ^^^^^^ help: convert the identifier to snake case: `foo_bar`
    |
 note: lint level defined here
   --> $DIR/lint-non-snake-case-modules.rs:1:9

src/test/ui/lint/lint-non-snake-case-no-lowercase-equivalent.rs

@@ -0,0 +1,12 @@
+// compile-pass
+
+#![allow(dead_code)]
+// pretty-expanded FIXME #23616
+
+#![feature(non_ascii_idents)]
+#![deny(non_snake_case)]
+
+// This name is neither upper nor lower case
+fn 你好() {}
+
+fn main() {}

src/test/ui/lint/lint-uppercase-variables.rs

@@ -7,20 +7,20 @@ mod foo {
 }
 
 struct Something {
-    X: usize //~ ERROR structure field `X` should have a snake case name such as `x`
+    X: usize //~ ERROR structure field `X` should have a snake case name
 }
 
-fn test(Xx: usize) { //~ ERROR variable `Xx` should have a snake case name such as `xx`
+fn test(Xx: usize) { //~ ERROR variable `Xx` should have a snake case name
     println!("{}", Xx);
 }
 
 fn main() {
-    let Test: usize = 0; //~ ERROR variable `Test` should have a snake case name such as `test`
+    let Test: usize = 0; //~ ERROR variable `Test` should have a snake case name
     println!("{}", Test);
 
     match foo::Foo::Foo {
         Foo => {}
-//~^ ERROR variable `Foo` should have a snake case name such as `foo`
+//~^ ERROR variable `Foo` should have a snake case name
 //~^^ WARN `Foo` is named the same as one of the variants of the type `foo::Foo`
 //~^^^ WARN unused variable: `Foo`
     }

src/test/ui/lint/lint-uppercase-variables.stderr

@@ -17,11 +17,11 @@ LL | #![warn(unused)]
    |         ^^^^^^
    = note: #[warn(unused_variables)] implied by #[warn(unused)]
 
-error: structure field `X` should have a snake case name such as `x`
+error: structure field `X` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:10:5
    |
-LL |     X: usize //~ ERROR structure field `X` should have a snake case name such as `x`
-   |     ^^^^^^^^
+LL |     X: usize //~ ERROR structure field `X` should have a snake case name
+   |     ^ help: convert the identifier to snake case: `x`
    |
 note: lint level defined here
   --> $DIR/lint-uppercase-variables.rs:3:9
@@ -29,23 +29,23 @@ note: lint level defined here
 LL | #![deny(non_snake_case)]
    |         ^^^^^^^^^^^^^^
 
-error: variable `Xx` should have a snake case name such as `xx`
+error: variable `Xx` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:13:9
    |
-LL | fn test(Xx: usize) { //~ ERROR variable `Xx` should have a snake case name such as `xx`
-   |         ^^
+LL | fn test(Xx: usize) { //~ ERROR variable `Xx` should have a snake case name
+   |         ^^ help: convert the identifier to snake case: `xx`
 
-error: variable `Test` should have a snake case name such as `test`
+error: variable `Test` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:18:9
    |
-LL |     let Test: usize = 0; //~ ERROR variable `Test` should have a snake case name such as `test`
-   |         ^^^^
+LL |     let Test: usize = 0; //~ ERROR variable `Test` should have a snake case name
+   |         ^^^^ help: convert the identifier to snake case: `test`
 
-error: variable `Foo` should have a snake case name such as `foo`
+error: variable `Foo` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:22:9
    |
 LL |         Foo => {}
-   |         ^^^
+   |         ^^^ help: convert the identifier to snake case: `foo`
 
 error: aborting due to 4 previous errors
 

src/test/ui/lint/reasons.stderr

@@ -11,11 +11,11 @@ note: lint level defined here
 LL | #![warn(elided_lifetimes_in_paths,
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
 
-warning: variable `Social_exchange_psychology` should have a snake case name such as `social_exchange_psychology`
+warning: variable `Social_exchange_psychology` should have a snake case name
   --> $DIR/reasons.rs:30:9
    |
 LL |     let Social_exchange_psychology = CheaterDetectionMechanism {};
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `social_exchange_psychology`
    |
    = note: people shouldn't have to change their usual style habits
            to contribute to our project

src/test/ui/regions/regions-fn-subtyping-return-static.rs

@@ -10,6 +10,7 @@
 
 #![allow(dead_code)]
 #![allow(unused_variables)]
+#![allow(non_snake_case)]
 
 struct S;
 

src/test/ui/regions/regions-fn-subtyping-return-static.stderr

@@ -1,26 +0,0 @@
-warning: function `want_F` should have a snake case name such as `want_f`
-  --> $DIR/regions-fn-subtyping-return-static.rs:18:1
-   |
-LL | fn want_F(f: F) { }
-   | ^^^^^^^^^^^^^^^^^^^
-   |
-   = note: #[warn(non_snake_case)] on by default
-
-warning: function `want_G` should have a snake case name such as `want_g`
-  --> $DIR/regions-fn-subtyping-return-static.rs:22:1
-   |
-LL | fn want_G(f: G) { }
-   | ^^^^^^^^^^^^^^^^^^^
-
-warning: function `supply_F` should have a snake case name such as `supply_f`
-  --> $DIR/regions-fn-subtyping-return-static.rs:39:1
-   |
-LL | / fn supply_F() {
-LL | |     want_F(foo);
-LL | |
-LL | |     want_F(bar);
-LL | |
-LL | |     want_F(baz);
-LL | | }
-   | |_^
-

src/test/ui/span/issue-24690.stderr

@@ -11,17 +11,17 @@ LL | #![warn(unused)]
    |         ^^^^^^
    = note: #[warn(unused_variables)] implied by #[warn(unused)]
 
-warning: variable `theTwo` should have a snake case name such as `the_two`
+warning: variable `theTwo` should have a snake case name
   --> $DIR/issue-24690.rs:12:9
    |
 LL |     let theTwo = 2; //~ WARN should have a snake case name
-   |         ^^^^^^
+   |         ^^^^^^ help: convert the identifier to snake case: `the_two`
    |
    = note: #[warn(non_snake_case)] on by default
 
-warning: variable `theOtherTwo` should have a snake case name such as `the_other_two`
+warning: variable `theOtherTwo` should have a snake case name
   --> $DIR/issue-24690.rs:13:9
    |
 LL |     let theOtherTwo = 2; //~ WARN should have a snake case name
-   |         ^^^^^^^^^^^
+   |         ^^^^^^^^^^^ help: convert the identifier to snake case: `the_other_two`