ICE more gracefully in constant evaluation when float parsing fails

Ideally float parsing wouldn't fail at all, but for the moment let's give a helpful message.

Fixes #31109

1 files changed, 15 insertions, 0 deletions

diff --git a/src/test/compile-fail/issue-31109.rs b/src/test/compile-fail/issue-31109.rs
new file mode 100644
index 00000000000..63b3d58b823
--- /dev/null
+++ b/src/test/compile-fail/issue-31109.rs
@@ -0,0 +1,15 @@
+// Copyright 2016 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.
+
+fn main() {
+    // FIXME(#31407) this error should go away, but in the meantime we test that it
+    // is accompanied by a somewhat useful error message.
+    let _: f64 = 1234567890123456789012345678901234567890e-340; //~ ERROR could not evaluate float
+}