fix #14912, make --useVersion:1.0 work again (#14945)

* fix #14912, make `--useVersion:1.0` work again
* a better fix
* add test

compiler/commands.nim

@@ -878,6 +878,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
       defineSymbol(conf.symbols, "NimPatch", "100")
       # old behaviors go here:
       defineSymbol(conf.symbols, "nimOldRelativePathBehavior")
+      undefSymbol(conf.symbols, "nimDoesntTrackDefects")
       ast.eqTypeFlags.excl {tfGcSafe, tfNoSideEffect}
       conf.globalOptions.incl optNimV1Emulation
     else:

tests/system/tuse_version.nim

@@ -0,0 +1,50 @@
+discard """
+  cmd: "nim c --useVersion:1.0 -r $file"
+  output: "1.0.100"
+"""
+
+{.warning[UnusedImport]: off.}
+
+import std/[
+  # Core:
+  bitops, typetraits, lenientops, macros, volatile,
+
+  # Algorithms:
+  algorithm, sequtils,
+
+  # Collections:
+  critbits, deques, heapqueue, intsets, lists, options, sets,
+  sharedlist, tables,
+
+  # Strings:
+  editdistance, wordwrap, parseutils, ropes,
+  pegs, punycode, strformat, strmisc, strscans, strtabs,
+  strutils, unicode, unidecode,
+
+  # Generic operator system services:
+  os, streams,
+
+  # Math libraries:
+  complex, math, mersenne, random, rationals, stats, sums,
+
+  # Internet protocols:
+  httpcore, mimetypes, uri,
+
+  # Parsers:
+  htmlparser, json, lexbase, parsecfg, parsecsv, parsesql, parsexml,
+
+  # XML processing:
+  xmltree, xmlparser,
+
+  # Generators:
+  htmlgen,
+
+  # Hashing:
+  base64, hashes,
+
+  # Miscellaneous:
+  colors, sugar, varints,
+]
+
+
+echo NimVersion