Implement mixed script confusable lint.

src/test/ui/lint/rfc-2457-non-ascii-idents/lint-mixed-script-confusables-2.rs

@@ -0,0 +1,20 @@
+// check-pass
+#![feature(non_ascii_idents)]
+#![deny(mixed_script_confusables)]
+
+struct ΑctuallyNotLatin;
+
+fn main() {
+    let λ = 42; // this usage of Greek confirms that Greek is used intentionally.
+}
+
+mod роре {
+    const エ: &'static str = "アイウ";
+
+    // this usage of Katakana confirms that Katakana is used intentionally.
+    fn ニャン() {
+        let д: usize = 100; // this usage of Cyrillic confirms that Cyrillic is used intentionally.
+
+        println!("meow!");
+    }
+}

src/test/ui/lint/rfc-2457-non-ascii-idents/lint-mixed-script-confusables.rs

@@ -0,0 +1,15 @@
+#![feature(non_ascii_idents)]
+#![deny(mixed_script_confusables)]
+
+struct ΑctuallyNotLatin;
+//~^ ERROR The usage of Script Group `Greek` in this crate consists solely of
+
+fn main() {
+    let v = ΑctuallyNotLatin;
+}
+
+mod роре {
+//~^ ERROR The usage of Script Group `Cyrillic` in this crate consists solely of
+    const エ: &'static str = "アイウ";
+    //~^ ERROR The usage of Script Group `Japanese, Katakana` in this crate consists solely of
+}

src/test/ui/lint/rfc-2457-non-ascii-idents/lint-mixed-script-confusables.stderr

@@ -0,0 +1,34 @@
+error: The usage of Script Group `Greek` in this crate consists solely of mixed script confusables
+  --> $DIR/lint-mixed-script-confusables.rs:4:8
+   |
+LL | struct ΑctuallyNotLatin;
+   |        ^^^^^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/lint-mixed-script-confusables.rs:2:9
+   |
+LL | #![deny(mixed_script_confusables)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: The usage includes 'Α' (U+0391).
+   = note: Please recheck to make sure their usages are indeed what you want.
+
+error: The usage of Script Group `Cyrillic` in this crate consists solely of mixed script confusables
+  --> $DIR/lint-mixed-script-confusables.rs:11:5
+   |
+LL | mod роре {
+   |     ^^^^
+   |
+   = note: The usage includes 'е' (U+0435), 'о' (U+043E), 'р' (U+0440).
+   = note: Please recheck to make sure their usages are indeed what you want.
+
+error: The usage of Script Group `Japanese, Katakana` in this crate consists solely of mixed script confusables
+  --> $DIR/lint-mixed-script-confusables.rs:13:11
+   |
+LL |     const エ: &'static str = "アイウ";
+   |           ^^
+   |
+   = note: The usage includes 'エ' (U+30A8).
+   = note: Please recheck to make sure their usages are indeed what you want.
+
+error: aborting due to 3 previous errors
+

src/test/ui/utf8_idents.rs

@@ -1,3 +1,5 @@
+#![allow(mixed_script_confusables)]
+
 fn foo<
     'β, //~ ERROR non-ascii idents are not fully supported
     γ  //~ ERROR non-ascii idents are not fully supported

src/test/ui/utf8_idents.stderr

@@ -1,5 +1,5 @@
 error[E0658]: non-ascii idents are not fully supported
-  --> $DIR/utf8_idents.rs:2:5
+  --> $DIR/utf8_idents.rs:4:5
    |
 LL |     'β,
    |     ^^
@@ -8,7 +8,7 @@ LL |     'β,
    = help: add `#![feature(non_ascii_idents)]` to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported
-  --> $DIR/utf8_idents.rs:3:5
+  --> $DIR/utf8_idents.rs:5:5
    |
 LL |     γ
    |     ^
@@ -17,7 +17,7 @@ LL |     γ
    = help: add `#![feature(non_ascii_idents)]` to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported
-  --> $DIR/utf8_idents.rs:8:5
+  --> $DIR/utf8_idents.rs:10:5
    |
 LL |     δ: usize
    |     ^
@@ -26,7 +26,7 @@ LL |     δ: usize
    = help: add `#![feature(non_ascii_idents)]` to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported
-  --> $DIR/utf8_idents.rs:12:9
+  --> $DIR/utf8_idents.rs:14:9
    |
 LL |     let α = 0.00001f64;
    |         ^
@@ -35,7 +35,7 @@ LL |     let α = 0.00001f64;
    = help: add `#![feature(non_ascii_idents)]` to the crate attributes to enable
 
 warning: type parameter `γ` should have an upper camel case name
-  --> $DIR/utf8_idents.rs:3:5
+  --> $DIR/utf8_idents.rs:5:5
    |
 LL |     γ
    |     ^ help: convert the identifier to upper camel case: `Γ`