nimsuggest knows how to deal with files not belonging to the project

compiler/msgs.nim

@@ -522,7 +522,7 @@ proc newFileInfo(fullPath, projPath: string): TFileInfo =
   if optEmbedOrigSrc in gGlobalOptions or true:
     result.lines = @[]
 
-proc fileInfoIdx*(filename: string): int32 =
+proc fileInfoIdx*(filename: string; isKnownFile: var bool): int32 =
   var
     canon: string
     pseudoPath = false
@@ -539,11 +539,16 @@ proc fileInfoIdx*(filename: string): int32 =
   if filenameToIndexTbl.hasKey(canon):
     result = filenameToIndexTbl[canon]
   else:
+    isKnownFile = false
     result = fileInfos.len.int32
     fileInfos.add(newFileInfo(canon, if pseudoPath: filename
                                      else: canon.shortenDir))
     filenameToIndexTbl[canon] = result
 
+proc fileInfoIdx*(filename: string): int32 =
+  var dummy: bool
+  result = fileInfoIdx(filename, dummy)
+
 proc newLineInfo*(fileInfoIdx: int32, line, col: int): TLineInfo =
   result.fileIndex = fileInfoIdx
   result.line = int16(line)

compiler/nimsuggest/nimsuggest.nim

@@ -87,8 +87,9 @@ proc action(cmd: string) =
   i += skipWhile(cmd, seps, i)
   i += parseInt(cmd, col, i)
 
+  var isKnownFile = true
   if orig.len == 0: err()
-  let dirtyIdx = orig.fileInfoIdx
+  let dirtyIdx = orig.fileInfoIdx(isKnownFile)
 
   if dirtyfile.len != 0: msgs.setDirtyFile(dirtyIdx, dirtyfile)
   else: msgs.setDirtyFile(dirtyIdx, nil)
@@ -99,7 +100,10 @@ proc action(cmd: string) =
   gTrackPos = newLineInfo(dirtyIdx, line, col)
   #echo dirtyfile, gDirtyBufferIdx, " project ", gProjectMainIdx
   gErrorCounter = 0
-  compileProject()
+  if not isKnownFile:
+    compileProject(dirtyIdx)
+  else:
+    compileProject()
 
 proc serve() =
   # do not stop after the first error: