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Diffstat (limited to 'doc/lispref/objects.texi')
| -rw-r--r-- | doc/lispref/objects.texi | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/doc/lispref/objects.texi b/doc/lispref/objects.texi index 78a7dccc88d..1253e46297f 100644 --- a/doc/lispref/objects.texi +++ b/doc/lispref/objects.texi @@ -2154,6 +2154,21 @@ Symbols}. @result{} nil @end group @end example + +@noindent +@cindex identical-contents objects, and byte-compiler +@cindex objects with identical contents, and byte-compiler +The Emacs Lisp byte compiler may collapse identical literal objects, +such as literal strings, into references to the same object, with the +effect that the byte-compiled code will compare such objects as +@code{eq}, while the interpreted version of the same code will not. +Therefore, your code should never rely on objects with the same +literal contents being either @code{eq} or not @code{eq}, it should +instead use functions that compare object contents such as +@code{equal}, described below. Similarly, your code should not modify +literal objects (e.g., put text properties on literal strings), since +doing that might affect other literal objects of the same contents, if +the byte compiler collapses them. @end defun @defun equal object1 object2 |