fix nim-lang#16334 (nim-lang#16335)

* fix nim-lang#16334

* rename isstdout -> isStdout

* separate lastMsgWasDot for stdout and stderr

* simplify logic

compiler/msgs.nim

@@ -16,11 +16,15 @@ import strutils2
 type InstantiationInfo* = typeof(instantiationInfo())
 template instLoc(): InstantiationInfo = instantiationInfo(-2, fullPaths = true)
 
-template flushDot(conf, stdorr) =
+template toStdOrrKind(stdOrr): untyped =
+  if stdOrr == stdout: stdOrrStdout else: stdOrrStderr
+
+template flushDot(conf, stdOrr) =
   ## safe to call multiple times
-  if conf.lastMsgWasDot:
-    conf.lastMsgWasDot = false
-    write(stdorr, "\n")
+  let stdOrrKind = stdOrr.toStdOrrKind()
+  if stdOrrKind in conf.lastMsgWasDot:
+    conf.lastMsgWasDot.excl stdOrrKind
+    write(stdOrr, "\n")
 
 proc toCChar*(c: char; result: var string) =
   case c
@@ -357,7 +361,7 @@ proc msgWrite(conf: ConfigRef; s: string) =
         stderr
     write(stdOrr, s)
     flushFile(stdOrr)
-    conf.lastMsgWasDot = true # subsequent writes need `flushDot`
+    conf.lastMsgWasDot.incl stdOrr.toStdOrrKind() # subsequent writes need `flushDot`
 
 template styledMsgWriteln*(args: varargs[typed]) =
   if not isNil(conf.writelnHook):

compiler/options.nim

@@ -240,6 +240,10 @@ type
   ProfileData* = ref object
     data*: TableRef[TLineInfo, ProfileInfo]
 
+  StdOrrKind* = enum
+    stdOrrStdout
+    stdOrrStderr
+
   ConfigRef* = ref object ## every global configuration
                           ## fields marked with '*' are subject to
                           ## the incremental compilation mechanisms
@@ -304,7 +308,7 @@ type
     projectPath*: AbsoluteDir # holds a path like /home/alice/projects/nim/compiler/
     projectFull*: AbsoluteFile # projectPath/projectName
     projectIsStdin*: bool # whether we're compiling from stdin
-    lastMsgWasDot*: bool # the last compiler message was a single '.'
+    lastMsgWasDot*: set[StdOrrKind] # the last compiler message was a single '.'
     projectMainIdx*: FileIndex # the canonical path id of the main module
     projectMainIdx2*: FileIndex # consider merging with projectMainIdx
     command*: string # the main command (e.g. cc, check, scan, etc)