Update compiler/rustc_middle/src/ty/consts/valtree.rs

Co-authored-by: Ralf Jung <post@ralfj.de>
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Oli Scherer 2021-03-16 18:31:25 +01:00 committed by GitHub
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@ -6,7 +6,8 @@ use rustc_macros::HashStable;
/// This datastructure is used to represent the value of constants used in the type system.
///
/// We explicitly choose a different datastructure from the way values are processed within
/// CTFE, as in the type system equal values must also have equal representation.
/// CTFE, as in the type system equal values (according to their `PartialEq`) must also have
/// equal representation (`==` on the rustc data structure, e.g. `ValTree`) and vice versa.
/// Since CTFE uses `AllocId` to represent pointers, it often happens that two different
/// `AllocId`s point to equal values. So we may end up with different representations for
/// two constants whose value is `&42`. Furthermore any kind of struct that has padding will