From: "drbrain (Eric Hodel)" Date: 2012-12-11T14:17:18+09:00 Subject: [ruby-core:50748] [ruby-trunk - Bug #7539] Misleading error message "can't convert nil into string" Issue #7539 has been updated by drbrain (Eric Hodel). I am worried about implying that the user should add to_str, to_ary, etc. to fix this problem. Rarely is implementing these methods appropriate since they are used for objects that are intended to behave exactly as a String, Array, etc. An error message that omitted mention of these methods can help prevent users from accidentally shooting themselves in the foot. ---------------------------------------- Bug #7539: Misleading error message "can't convert nil into string" https://bugs.ruby-lang.org/issues/7539#change-34599 Author: connec (Chris Connelly) Status: Open Priority: Normal Assignee: Category: core Target version: next minor ruby -v: ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-linux] When trying to call `String#+` with `nil` as an argument, you get the error "can't convert nil into String", which does not make sense (in fact seeming blatantly false) as `nil.to_s`, `String(nil)` etc. all return `''` without errors. Ideally, this method should use `to_s` to convert the argument, or else report an error along the lines of "can't append nil to string". Minimal test case: Actual: > '' + nil TypeError: can't convert nil into String Expected: > '' + nil '' -- http://bugs.ruby-lang.org/