add test

rustfmt.toml

@@ -5,3 +5,4 @@ wrap_comments = true
 edition = "2021"
 error_on_line_overflow = true
 version = "Two"
+ignore = ["tests/ui/crashes/ice-10912.rs"]

tests/ui/crashes/ice-10912.rs

@@ -0,0 +1,4 @@
+#![warn(clippy::unreadable_literal)]
+fn f2() -> impl Sized { && 3.14159265358979323846E }
+
+fn main() {}

tests/ui/crashes/ice-10912.stderr

@@ -0,0 +1,16 @@
+error: expected at least one digit in exponent
+  --> $DIR/ice-10912.rs:2:28
+   |
+LL | fn f2() -> impl Sized { && 3.14159265358979323846E }
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: long literal lacking separators
+  --> $DIR/ice-10912.rs:2:28
+   |
+LL | fn f2() -> impl Sized { && 3.14159265358979323846E }
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^ help: consider: `3.141_592_653_589_793_238_46`
+   |
+   = note: `-D clippy::unreadable-literal` implied by `-D warnings`
+
+error: aborting due to 2 previous errors
+