From: "rits (First Last)" Date: 2013-12-17T11:09:02+09:00 Subject: [ruby-core:59151] [ruby-trunk - Bug #9251] ! operator has lower precedence than = in an assignment expression Issue #9251 has been updated by rits (First Last). > Operators have not only precedence, but also associativity. Assignment operator has right associativity. Associativity is not involved here: a && b = c && d The associativity of an operator specifies the order of evaluation when the same operator (or operators with the same precedence) appear sequentially in an expression = and && are different operators with different precedence As I said, in the above expression, = shows both higher (on the left) and lower (on the right) precedence than && at the same time. You did not address my last post, it's pretty clear there that this lvalue exception leads to nothing but trouble. ---------------------------------------- Bug #9251: ! operator has lower precedence than = in an assignment expression https://bugs.ruby-lang.org/issues/9251#change-43712 Author: rits (First Last) Status: Feedback Priority: Low Assignee: Category: doc Target version: ruby -v: ruby 2.0.0p353 (2013-11-22 revision 43784) [i686-linux] Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN irb(main):001:0> !a = 1 (irb):1: warning: found = in conditional, should be == => false irb(main):002:0> a => 1 ! is supposed to have higher precedence than =, so !a = 1 should be (!a) = 1, and thus an error, not !(a = 1) -- http://bugs.ruby-lang.org/