Auto merge of #51075 - estebank:and_the_case_of_the_confusable_float_exponent, r=eddyb

Check for confusable Unicode chars in float literal exponent

Fixing tests for #49989. Resolves #49746.

src/test/parse-fail/unicode-chars.rs

@@ -13,5 +13,5 @@
 fn main() {
     let y = 0;
     //~^ ERROR unknown start of token: \u{37e}
-    //~^^ HELP unicode character ';' (Greek Question Mark) looks like ';' (Semicolon), but it's not
+    //~^^ HELP Unicode character ';' (Greek Question Mark) looks like ';' (Semicolon), but it is not
 }

src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.rs

@@ -0,0 +1,14 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e−11; // m³⋅kg⁻¹⋅s⁻²
+//~^ ERROR expected at least one digit in exponent
+
+fn main() {}

src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr

@@ -0,0 +1,12 @@
+error: expected at least one digit in exponent
+  --> $DIR/issue-49746-unicode-confusable-in-float-literal-expt.rs:11:53
+   |
+LL | const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e−11; // m³⋅kg⁻¹⋅s⁻²
+   |                                                     ^
+help: Unicode character '−' (Minus Sign) looks like '-' (Minus/Hyphen), but it is not
+   |
+LL | const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e-11; // m³⋅kg⁻¹⋅s⁻²
+   |                                                     ^
+
+error: aborting due to previous error
+