make tests green again

changelog.md

@@ -10,3 +10,5 @@
   in ``system.nim`` and do the right thing.
 - JSON: Deprecated `getBVal`, `getFNum`, and `getNum` in favour to
   `getBool`, `getFloat`, `getBiggestInt`. Also `getInt` procedure was added.
+- ``echo`` now works with strings that contain ``\0`` (the binary zero is not
+  shown) and ``nil`` strings are equal to empty strings.

compiler/ccgexprs.nim

@@ -978,9 +978,12 @@ proc genEcho(p: BProc, n: PNode) =
     p.module.includeHeader("<base/log.h>")
     linefmt(p, cpsStmts, """Genode::log(""$1);$n""", args)
   else:
-    var a: TLoc
+    if n.len == 0:
-    initLocExpr(p, n, a)
+      linefmt(p, cpsStmts, "#echoBinSafe(NIM_NIL, $1);$n", n.len.rope)
-    linefmt(p, cpsStmts, "#echoBinSafe($1, $2);$n", a.rdLoc, n.len.rope)
+    else:
+      var a: TLoc
+      initLocExpr(p, n, a)
+      linefmt(p, cpsStmts, "#echoBinSafe($1, $2);$n", a.rdLoc, n.len.rope)
     when false:
       p.module.includeHeader("<stdio.h>")
       linefmt(p, cpsStmts, "printf($1$2);$n",

tests/ccgbugs/tret_arg_init.nim

@@ -1,7 +1,7 @@
 discard """
-  output: '''nil
+  output: '''
-nil
+
-nil'''
+'''
 """
 
 type Bar = object

tests/concepts/tmapconcept.nim

@@ -1,7 +1,7 @@
 discard """
 output: '''10
 10
-nil
+
 1'''
 msg: '''
 K=string V=int