fixes #11294

compiler/commands.nim

@@ -106,7 +106,7 @@ proc writeCommandLineUsage*(conf: ConfigRef) =
   msgWriteln(conf, getCommandLineDesc(conf), {msgStdout})
 
 proc addPrefix(switch: string): string =
-  if len(switch) == 1: result = "-" & switch
+  if len(switch) <= 1: result = "-" & switch
   else: result = "--" & switch
 
 const
@@ -770,6 +770,8 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     processOnOffSwitchG(conf, {optDocInternal}, arg, pass, info)
   of "multimethods":
     processOnOffSwitchG(conf, {optMultiMethods}, arg, pass, info)
+  of "":
+    conf.projectName = "-"
   else:
     if strutils.find(switch, '.') >= 0: options.setConfigVar(conf, switch, arg)
     else: invalidCmdLineOption(conf, pass, switch, info)

lib/pure/parseopt.nim

@@ -274,8 +274,9 @@ when declared(os.paramCount):
 proc handleShortOption(p: var OptParser; cmd: string) =
   var i = p.pos
   p.kind = cmdShortOption
-  add(p.key.string, cmd[i])
-  inc(i)
+  if i < cmd.len:
+    add(p.key.string, cmd[i])
+    inc(i)
   p.inShortState = true
   while i < cmd.len and cmd[i] in {'\t', ' '}:
     inc(i)
@@ -446,7 +447,7 @@ when declared(initOptParser):
              tuple[kind: CmdLineKind, key, val: TaintedString] =
     ## Convenience iterator for iterating over command line arguments.
     ##
-    ## This creates a new `OptParser<#OptParser>`_. If no command line 
+    ## This creates a new `OptParser<#OptParser>`_. If no command line
     ## arguments are provided, the real command line as provided by the
     ## ``os`` module is retrieved instead.
     ##