Maybe collectively we can. In Emacs/SLIME/CCL,SBCL on ARM32,x86-64 ESC + '.' (command 'find-tag') on a symbol in the REPL opens a buffer with the definition of that symbol, provided you have the sources (it's neither decompiling nor reading the definition from the binary, but follows a hint to the source file). So this is more functionality of the environment / tools, rather then the compiler or language. Works beautifully though and in most cases you don't really want the sources embedded within the binary.
Didn't even know about this one. It is one of those 'optional' features -- the standard puts it like "Any implementation may legitimately return nil as the lambda-expression of any function." And indeed, CCL choses to do just that. SBCL seems to put in some effort to decompile the function.
Worst case scenario, you can probably patch your compiler's COMPILE function to store the data somewhere before performing the actual compilation.
As for CCL, it seems to work for me just fine as long as you set CCL:*SAVE-DEFINITIONS* to T:
Clozure Common Lisp Version 1.12.1 (v1.12.1) LinuxX8664
For more information about CCL, please see http://ccl.clozure.com.
CCL is free software. It is distributed under the terms of the Apache
Licence, Version 2.0.
? (defun foobar (a b c) (* a (+ b c)))
FOOBAR
? (function-lambda-expression #'foobar)
NIL
NIL
FOOBAR
? (setf ccl:*save-definitions* t)
T
? (defun foobar (a b c) (* a (+ b c)))
FOOBAR
? (function-lambda-expression #'foobar)
(LAMBDA (A B C) (DECLARE (CCL::GLOBAL-FUNCTION-NAME FOOBAR)) (BLOCK FOOBAR (* A (+ B C))))
NIL
FOOBAR
Not a Common Lisp implementation but Clojure can find the source for a symbol (provided the source code file is in the classpath) with the clojure.repl/source function (doc: https://clojure.github.io/clojure/clojure.repl-api.html#cloj... .) All development environments support jump to definition.