Issue #18518 has been updated by headius (Charles Nutter). There's no practical reason to support left shift of greater than integer max, so I would support a fast check and RangeError. It would make more sense than just blowing up memory and raising NoMemoryError for something that should never work (1 << (`2**32`) produces a big integer at least 2^29 bytes wide, more than 0.5GB). ---------------------------------------- Bug #18518: NoMemoryError + [FATAL] failed to allocate memory for twice 1 << large https://bugs.ruby-lang.org/issues/18518#change-101101 * Author: Eregon (Benoit Daloze) * Status: Open * Priority: Normal * ruby -v: ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-linux] * Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- Repro: ```ruby exp = 2**40 # also fails with bignum e.g. 2**64 def exc begin yield rescue NoMemoryError => e p :NoMemoryError end end p exp exc { (1 << exp) } exc { (-1 << exp) } exc { (bignum_value << exp) } exc { (-bignum_value << exp) } ``` Output: ``` $ ruby -v mri_oom.rb ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-linux] mri_oom.rb:7: warning: assigned but unused variable - e 1099511627776 :NoMemoryError [FATAL] failed to allocate memory ``` 3.1.0 seems fine: ``` $ ruby -v mri_oom.rb ruby 3.1.0p0 (2021-12-25 revision fb4df44d16) [x86_64-linux] mri_oom.rb:7: warning: assigned but unused variable - e 1099511627776 :NoMemoryError :NoMemoryError :NoMemoryError :NoMemoryError ``` -- https://bugs.ruby-lang.org/