revert strictDefs as the default (#24620)

revert https://github.com/nim-lang/Nim/pull/24225

see also https://forum.nim-lang.org/t/12646

compiler/condsyms.nim

@@ -172,4 +172,3 @@ proc initDefines*(symbols: StringTableRef) =
   defineSymbol("nimHasDefaultFloatRoundtrip")
   defineSymbol("nimHasXorSet")
 
-  defineSymbol("nimHasLegacyNoStrictDefs")

compiler/nim.cfg

@@ -49,7 +49,7 @@ define:useStdoutAsStdmsg
 
 
 @if nimUseStrictDefs:
-  experimental:strictDefs # deadcode
+  experimental:strictDefs
   warningAsError[Uninit]:on
   warningAsError[ProveInit]:on
 @end

compiler/options.nim

@@ -248,8 +248,6 @@ type
       ## Useful for libraries that rely on local passC
     jsNoLambdaLifting
       ## Old transformation for closures in JS backend
-    noStrictDefs
-      ## disable "strictdefs"
 
   SymbolFilesOption* = enum
     disabledSf, writeOnlySf, readOnlySf, v2Sf, stressTest

compiler/semexprs.nim

@@ -878,7 +878,7 @@ proc newHiddenAddrTaken(c: PContext, n: PNode, isOutParam: bool): PNode =
     if aa notin {arLValue, arLocalLValue}:
       if aa == arDiscriminant and c.inUncheckedAssignSection > 0:
         discard "allow access within a cast(unsafeAssign) section"
-      elif noStrictDefs notin c.config.legacyFeatures and aa == arAddressableConst and
+      elif strictDefs in c.features and aa == arAddressableConst and
               sym != nil and sym.kind == skLet and isOutParam:
         discard "allow let varaibles to be passed to out parameters"
       else:
@@ -2068,8 +2068,7 @@ proc semAsgn(c: PContext, n: PNode; mode=asgnNormal): PNode =
   let root = getRoot(a)
   let useStrictDefLet = root != nil and root.kind == skLet and
                        assignable == arAddressableConst and
-                       noStrictDefs notin c.config.legacyFeatures and
-                       isLocalSym(root)
+                       strictDefs in c.features and isLocalSym(root)
   if le == nil:
     localError(c.config, a.info, "expression has no type")
   elif (skipTypes(le, {tyGenericInst, tyAlias, tySink}).kind notin {tyVar} and

compiler/sempass2.nim

@@ -221,7 +221,7 @@ proc initVar(a: PEffects, n: PNode; volatileCheck: bool) =
     if volatileCheck: makeVolatile(a, s)
     for x in a.init:
       if x == s.id:
-        if noStrictDefs notin a.c.config.legacyFeatures and s.kind == skLet:
+        if strictDefs in a.c.features and s.kind == skLet:
           localError(a.config, n.info, errXCannotBeAssignedTo %
                     renderTree(n, {renderNoComments}
                 ))
@@ -379,7 +379,7 @@ proc useVar(a: PEffects, n: PNode) =
       if s.typ.requiresInit:
         message(a.config, n.info, warnProveInit, s.name.s)
       elif a.leftPartOfAsgn <= 0:
-        if noStrictDefs notin a.c.config.legacyFeatures:
+        if strictDefs in a.c.features:
           if s.kind == skLet:
             localError(a.config, n.info, errLetNeedsInit)
           else:
@@ -1664,7 +1664,7 @@ proc trackProc*(c: PContext; s: PSym, body: PNode) =
 
   if not isEmptyType(s.typ.returnType) and
      (s.typ.returnType.requiresInit or s.typ.returnType.skipTypes(abstractInst).kind == tyVar or
-       noStrictDefs notin c.config.legacyFeatures) and
+       strictDefs in c.features) and
      s.kind in {skProc, skFunc, skConverter, skMethod} and s.magic == mNone and
      sfNoInit notin s.flags:
     var res = s.ast[resultPos].sym # get result symbol

compiler/semstmts.nim

@@ -975,7 +975,7 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
           else:
             checkNilable(c, v)
           # allow let to not be initialised if imported from C:
-          if v.kind == skLet and sfImportc notin v.flags and (noStrictDefs in c.config.legacyFeatures or not isLocalSym(v)):
+          if v.kind == skLet and sfImportc notin v.flags and (strictDefs notin c.features or not isLocalSym(v)):
             localError(c.config, a.info, errLetNeedsInit)
         if sfCompileTime in v.flags:
           var x = newNodeI(result.kind, v.info)

compiler/sigmatch.nim

@@ -2251,7 +2251,7 @@ proc isLValue(c: PContext; n: PNode, isOutParam = false): bool {.inline.} =
     result = c.inUncheckedAssignSection > 0
   of arAddressableConst:
     let sym = getRoot(n)
-    result = noStrictDefs notin c.config.legacyFeatures and sym != nil and sym.kind == skLet and isOutParam
+    result = strictDefs in c.features and sym != nil and sym.kind == skLet and isOutParam
   else:
     result = false
 

config/config.nims

@@ -21,4 +21,3 @@ when defined(nimStrictMode):
     # future work: XDeclaredButNotUsed
 
 switch("define", "nimVersion:" & NimVersion) # deadcode
-switch("experimental", "strictDefs")

tests/msgs/twarningaserror.nim

@@ -1,5 +1,4 @@
 discard """
-  matrix: "--legacy:nostrictdefs"
   joinable: false
 """