diff --git a/src/nimble.nim b/src/nimble.nim
index fc2a3a0..f0d8878 100644
--- a/src/nimble.nim
+++ b/src/nimble.nim
@@ -622,7 +622,6 @@ proc listPaths(options: Options) =
   ## On success the proc returns normally.
   cli.setSuppressMessages(true)
   assert options.action.typ == actionPath
-  assert(not options.action.packages.isNil)
 
   if options.action.packages.len == 0:
     raise newException(NimbleError, "A package name needs to be specified")
diff --git a/src/nimblepkg/download.nim b/src/nimblepkg/download.nim
index cad8d3d..226fe27 100644
--- a/src/nimblepkg/download.nim
+++ b/src/nimblepkg/download.nim
@@ -166,9 +166,6 @@ proc doDownload(url: string, downloadDir: string, verRange: VersionRange,
     meth
     if $latest.ver != "":
       result = latest.ver
-    else:
-      # Result should already be set to #head here.
-      assert(not result.isNil)
 
   removeDir(downloadDir)
   if verRange.kind == verSpecial:
diff --git a/src/nimblepkg/nimscriptsupport.nim b/src/nimblepkg/nimscriptsupport.nim
index 91ab7ff..0de2010 100644
--- a/src/nimblepkg/nimscriptsupport.nim
+++ b/src/nimblepkg/nimscriptsupport.nim
@@ -51,7 +51,7 @@ proc getGlobal(g: ModuleGraph; ident: PSym): string =
   else:
     let n = vm.globalCtx.getGlobalValue(ident)
   if n.isStrLit:
-    result = if n.strVal.isNil: "" else: n.strVal
+    result = n.strVal
   else:
     raiseVariableError(ident.name.s, "string")
 
diff --git a/src/nimblepkg/packageinfo.nim b/src/nimblepkg/packageinfo.nim
index e6e3726..6306840 100644
--- a/src/nimblepkg/packageinfo.nim
+++ b/src/nimblepkg/packageinfo.nim
@@ -371,8 +371,7 @@ proc findPkg*(pkglist: seq[tuple[pkgInfo: PackageInfo, meta: MetaData]],
     if cmpIgnoreStyle(pkg.pkginfo.name, dep.name) != 0 and
        cmpIgnoreStyle(pkg.meta.url, dep.name) != 0: continue
     if withinRange(pkg.pkgInfo, dep.ver):
-      let isNewer = (not r.version.isNil) and
-                    newVersion(r.version) < newVersion(pkg.pkginfo.version)
+      let isNewer = newVersion(r.version) < newVersion(pkg.pkginfo.version)
       if not result or isNewer:
         r = pkg.pkginfo
         result = true
diff --git a/src/nimblepkg/packageinstaller.nim b/src/nimblepkg/packageinstaller.nim
index e48a910..125db93 100644
--- a/src/nimblepkg/packageinstaller.nim
+++ b/src/nimblepkg/packageinstaller.nim
@@ -81,7 +81,7 @@ proc saveNimbleMeta*(pkgDestDir, url, vcsRevision: string,
   ##
   ## isLink - Determines whether the installed package is a .nimble-link.
   var nimblemeta = %{"url": %url}
-  if not vcsRevision.isNil:
+  if vcsRevision.len > 0:
     nimblemeta["vcsRevision"] = %vcsRevision
   let files = newJArray()
   nimblemeta["files"] = files
diff --git a/src/nimblepkg/version.nim b/src/nimblepkg/version.nim
index e19e45b..6b1e7df 100644
--- a/src/nimblepkg/version.nim
+++ b/src/nimblepkg/version.nim
@@ -39,8 +39,6 @@ proc `$`*(ver: Version): string {.borrow.}
 
 proc hash*(ver: Version): Hash {.borrow.}
 
-proc isNil*(ver: Version): bool {.borrow.}
-
 proc newVersion*(ver: string): Version =
   doAssert(ver.len == 0 or ver[0] in {'#', '\0'} + Digits,
            "Wrong version: " & ver)