Steps to reproduce:
1. Open attached project.
2. Open scene named "main".
3. In the "Hierarchy" window select UI object named "Button".
4. In the "Inspector" press on width or height field of "Rect Transform" component to enter a number.
5. Try pressing any number key until entered number becomes so large that the Editor starts hanging or crashes.

Expected result:
The Editor should not hang/crash when a large number is entered or there should be some limits that would define how large can be the number that a specific field can contain.

Reproduced with:
5.2.4f1, 5.3.4f1, 5.3.5f1, 5.3.5p1, 5.4.0b18.

Cannot reproduce with:
5.1.0f3.

Workaround:
It seems to work when using a copy-paste method to enter a number and not entering all the digits one-by-one using numeric keypad.

Note: GIF attached. Also, user attached a short video that clearly explains the issue.