underscore as special word (#21766)

* underscore as special word

* fix really hard to notice error

(cherry picked from commit ca82b4ea16)

compiler/lookups.nim

@@ -11,7 +11,7 @@
 import std/[algorithm, strutils, tables]
 import
   intsets, ast, astalgo, idents, semdata, types, msgs, options,
-  renderer, nimfix/prettybase, lineinfos, modulegraphs, astmsgs
+  renderer, nimfix/prettybase, lineinfos, modulegraphs, astmsgs, wordrecg
 
 proc ensureNoMissingOrUnusedSymbols(c: PContext; scope: PScope)
 
@@ -311,10 +311,10 @@ proc wrongRedefinition*(c: PContext; info: TLineInfo, s: string;
 proc addDeclAt*(c: PContext; scope: PScope, sym: PSym, info: TLineInfo) =
   let conflict = scope.addUniqueSym(sym)
   if conflict != nil:
-    if sym.kind == skModule and conflict.kind == skModule:      
+    if sym.kind == skModule and conflict.kind == skModule:
       # e.g.: import foo; import foo
       # xxx we could refine this by issuing a different hint for the case
-      # where a duplicate import happens inside an include.      
+      # where a duplicate import happens inside an include.
       if c.importModuleMap[sym.id] == c.importModuleMap[conflict.id]:
         #only hints if the conflict is the actual module not just a shared name
         localError(c.config, info, hintDuplicateModuleImport,

compiler/sempass2.nim

@@ -1076,7 +1076,7 @@ proc track(tracked: PEffects, n: PNode) =
       elif child.kind == nkVarTuple and last.kind != nkEmpty:
         for i in 0..<child.len-1:
           if child[i].kind == nkEmpty or
-            child[i].kind == nkSym and child[i].sym.name.s == "_":
+            child[i].kind == nkSym and child[i].sym.name.id == ord(wUnderscore):
             continue
           initVar(tracked, child[i], volatileCheck=false)
           if last.kind in {nkPar, nkTupleConstr}:

compiler/semstmts.nim

@@ -388,7 +388,7 @@ proc addToVarSection(c: PContext; result: PNode; orig, identDefs: PNode) =
     result.add identDefs
 
 proc isDiscardUnderscore(v: PSym): bool =
-  if v.name.s == "_":
+  if v.name.id == ord(wUnderscore):
     v.flags.incl(sfGenSym)
     result = true
 

compiler/semtempl.nim

@@ -228,7 +228,7 @@ proc addLocalDecl(c: var TemplCtx, n: var PNode, k: TSymKind) =
           closeScope(c)
     let ident = getIdentNode(c, n)
     if not isTemplParam(c, ident):
-      if n.kind != nkSym and not (n.kind == nkIdent and n.ident.s == "_"):
+      if n.kind != nkSym and not (n.kind == nkIdent and n.ident.id == ord(wUnderscore)):
         let local = newGenSym(k, ident, c)
         addPrelimDecl(c.c, local)
         styleCheckDef(c.c, n.info, local)

compiler/wordrecg.nim

@@ -32,6 +32,7 @@ type
 
     wColon = ":", wColonColon = "::", wEquals = "=", wDot = ".", wDotDot = "..",
     wStar = "*", wMinus = "-",
+    wUnderscore = "_",
     wMagic = "magic", wThread = "thread", wFinal = "final", wProfiler = "profiler",
     wMemTracker = "memtracker", wObjChecks = "objchecks",
     wIntDefine = "intdefine", wStrDefine = "strdefine", wBoolDefine = "booldefine",