Merge branch 'devel' into pr_field

compiler/ast.nim

@@ -1647,9 +1647,13 @@ proc canRaise*(fn: PNode): bool =
     if fn.typ.n[0].kind == nkSym:
       result = false
     else:
+      # A proc-typed value with no explicit raises slot still has
+      # unspecified effects, which sempass2 treats conservatively.
+      # Codegen needs to do the same in order to keep goto-exception
+      # checks after indirect/closure calls.
       result = ((fn.typ.n[0].len < effectListLen) or
-        (fn.typ.n[0][exceptionEffects] != nil and
-        fn.typ.n[0][exceptionEffects].safeLen > 0))
+        fn.typ.n[0][exceptionEffects] == nil or
+        fn.typ.n[0][exceptionEffects].safeLen > 0)
   else:
     result = false
 

compiler/ccgexprs.nim

@@ -1904,7 +1904,9 @@ proc genObjConstr(p: BProc, e: PNode, d: var TLoc) =
 
   var tmp: TLoc = default(TLoc)
   var r: Rope
-  let needsZeroMem = p.config.selectedGC notin {gcArc, gcAtomicArc, gcOrc, gcYrc} or nfAllFieldsSet notin e.flags
+  let needsZeroMem =
+    nfAllFieldsSet notin e.flags or
+    (optSeqDestructors notin p.config.globalOptions and containsGarbageCollectedRef(t))
   if useTemp:
     tmp = getTemp(p, t)
     r = rdLoc(tmp)
@@ -2816,9 +2818,9 @@ proc genWasMoved(p: BProc; n: PNode) =
     #  [addrLoc(p.config, a), getTypeDesc(p.module, a.t)])
 
 proc genMove(p: BProc; n: PNode; d: var TLoc) =
-  var a: TLoc = initLocExpr(p, n[1].skipAddr, {lfEnforceDeref, lfPrepareForMutation})
   if n.len == 4:
     # generated by liftdestructors:
+    var a: TLoc = initLocExpr(p, n[1].skipAddr, {lfEnforceDeref, lfPrepareForMutation})
     var src: TLoc = initLocExpr(p, n[2])
     let destVal = rdLoc(a)
     let srcVal = rdLoc(src)
@@ -2838,29 +2840,16 @@ proc genMove(p: BProc; n: PNode; d: var TLoc) =
   else:
     if d.k == locNone: d = getTemp(p, n.typ)
     if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc}:
-      genAssignment(p, d, a, {})
       var op = getAttachedOp(p.module.g.graph, n.typ, attachedWasMoved)
-      if op == nil:
+      if op == nil or sfOverridden notin op.flags:
+        var a: TLoc = initLocExpr(p, n[1].skipAddr, {lfEnforceDeref, lfPrepareForMutation})
+        genAssignment(p, d, a, {})
         resetLoc(p, a)
       else:
-        var b = initLocExpr(p, newSymNode(op))
-        case skipTypes(a.t, abstractVar+{tyStatic}).kind
-        of tyOpenArray, tyVarargs: # todo fixme generated `wasMoved` hooks for
-                                   # openarrays, but it probably shouldn't?
-          let ra = rdLoc(a)
-          var s: string
-          if reifiedOpenArray(a.lode):
-            if a.t.kind in {tyVar, tyLent}:
-              s = derefField(ra, "Field0") & cArgumentSeparator & derefField(ra, "Field1")
-            else:
-              s = dotField(ra, "Field0") & cArgumentSeparator & dotField(ra, "Field1")
-          else:
-            s = ra & cArgumentSeparator & ra & "Len_0"
-          p.s(cpsStmts).addCallStmt(rdLoc(b), s)
-        else:
-          let val = if p.module.compileToCpp: rdLoc(a) else: byRefLoc(p, a)
-          p.s(cpsStmts).addCallStmt(rdLoc(b), val)
+        n[1] = makeAddr(n[1], p.module.idgen)
+        genCall(p, n, d)
     else:
+      var a: TLoc = initLocExpr(p, n[1].skipAddr, {lfEnforceDeref, lfPrepareForMutation})
       genAssignment(p, d, a, {})
       resetLoc(p, a)
 

compiler/ccgstmts.nim

@@ -341,9 +341,9 @@ proc genCppParamsForCtor(p: BProc; call: PNode; didGenTemp: var bool): Snippet =
           call[i][0]
         else:
           call[i]
-      if param.kind != nkBracketExpr or param.typ.kind in
+      if not param.typ.isCompileTimeOnly and (param.kind != nkBracketExpr or param.typ.kind in
         {tyRef, tyPtr, tyUncheckedArray, tyArray, tyOpenArray,
-          tyVarargs, tySequence, tyString, tyCstring, tyTuple}:
+          tyVarargs, tySequence, tyString, tyCstring, tyTuple}):
         let tempLoc = initLocExprSingleUse(p, param)
         didGenTemp = didGenTemp or tempLoc.k == locTemp
       genOtherArg(p, call, i, typ, res, argBuilder)
@@ -1237,6 +1237,7 @@ proc genTryCpp(p: BProc, t: PNode, d: var TLoc) =
         else:
           scope = initScope(p.s(cpsStmts))
       # we handled the error:
+      linefmt(p, cpsStmts, "T$1_ = nullptr;$n", [etmp])
       expr(p, t[i][0], d)
       linefmt(p, cpsStmts, "#popCurrentException();$n", [])
       endBlockWith(p):

compiler/guards.nim

@@ -46,7 +46,7 @@ proc isLocation(n: PNode): bool = not n.isValue
 
 proc isLet(n: PNode): bool =
   if n.kind == nkSym:
-    if n.sym.kind in {skLet, skTemp, skForVar}:
+    if n.sym.kind in {skLet, skConst, skTemp, skForVar}: # guard immutable variables
       result = true
     elif n.sym.kind == skParam and skipTypes(n.sym.typ,
                                              abstractInst).kind notin {tyVar}:

compiler/injectdestructors.nim

@@ -803,6 +803,23 @@ proc hasCustomDestructor(c: Con, t: PType): bool =
     obj = skipTypes(obj.baseClass, abstractPtrs)
     result = result or isCustomDestructor(c, obj)
 
+const
+  exprBranchKinds = {nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt,
+                     nkTryStmt, nkPragmaBlock}
+
+proc distributeAsgn(asgnKind: TNodeKind; dest, ri: PNode; c: var Con; s: var Scope): PNode =
+  ## Distributes an assignment ``dest = ri`` into the leaf expressions of
+  ## ``ri`` when ``ri`` is an expression-based control flow construct. This
+  ## avoids creating pointless intermediate temporaries (bug #25850). The
+  ## descent is recursive so that nestings like ``block: ...; if c: a else: b``
+  ## assign directly to ``dest`` instead of going through a temp per branch.
+  if ri.kind in exprBranchKinds:
+    template process(child, s): untyped =
+      distributeAsgn(asgnKind, dest, child, c, s)
+    handleNestedTempl(ri, process, willProduceStmt = true)
+  else:
+    result = newTree(asgnKind, dest, p(ri, c, s, consumed))
+
 proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSingleUsedTemp}; inReturn = false): PNode =
   if n.kind in {nkStmtList, nkStmtListExpr, nkBlockStmt, nkBlockExpr, nkIfStmt,
                 nkIfExpr, nkCaseStmt, nkWhen, nkWhileStmt, nkParForStmt, nkTryStmt, nkPragmaBlock}:
@@ -1004,13 +1021,11 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
         result = moveOrCopy(p(n[0], c, s, mode), n[1], c, s, flags)
       elif isDiscriminantField(n[0]):
         result = c.genDiscriminantAsgn(s, n)
-      elif n[1].kind in {nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt, nkTryStmt, nkPragmaBlock}:
+      elif n[1].kind in exprBranchKinds:
         # Distribute the assignment into each branch to avoid
         # creating pointless temporaries for expression-based control flow.
         let dest = p(n[0], c, s, mode)
-        template process(child, s): untyped =
-          newTree(n.kind, dest, p(child, c, s, consumed))
-        handleNestedTempl(n[1], process, willProduceStmt = true)
+        result = distributeAsgn(n.kind, dest, n[1], c, s)
       else:
         result = copyNode(n)
         result.add p(n[0], c, s, mode)

compiler/lexer.nim

@@ -1349,7 +1349,7 @@ proc rawGetTok*(L: var Lexer, tok: var Token) =
           lexMessage(L, errGenerated, "invalid token: no whitespace between number and identifier")
     of '-':
       if L.buf[L.bufpos+1] in {'0'..'9'} and
-          (L.bufpos-1 == 0 or L.buf[L.bufpos-1] in UnaryMinusWhitelist):
+          (L.bufpos == 0 or L.buf[L.bufpos-1] in UnaryMinusWhitelist):
         # x)-23 # binary minus
         # ,-23  # unary minus
         # \n-78 # unary minus? Yes.

compiler/lineinfos.nim

@@ -100,6 +100,7 @@ type
     warnGlobalVarConstructorTemporary = "GlobalVarConstructorTemporary",
     warnImplicitRangeConversion = "ImplicitRangeConversion",
     warnSystemRangeConversion = "SystemRangeConversion",
+    warnInvalidCmpOp = "InvalidCmpOp",
     # hints
     hintSuccess = "Success", hintSuccessX = "SuccessX",
     hintCC = "CC",
@@ -210,6 +211,7 @@ const
     warnGlobalVarConstructorTemporary: "global variable '$1' initialization requires a temporary variable",
     warnImplicitRangeConversion: "implicit range conversion $1",
     warnSystemRangeConversion: "implicit range conversion $1",
+    warnInvalidCmpOp: "$1",
     hintSuccess: "operation successful: $#",
     # keep in sync with `testament.isSuccess`
     hintSuccessX: "$build\n$loc lines; ${sec}s; $mem; proj: $project; out: $output",

compiler/lookups.nim

@@ -459,6 +459,15 @@ proc openShadowScope*(c: PContext) =
                           symbols: initStrTable(),
                           depthLevel: c.scopeDepth)
 
+proc rememberShadowDefs*(c: PContext) =
+  ## bug #25693: a template/macro operand's local definitions are sem-checked in
+  ## a shadow scope that is then discarded. Record those definitions so that a
+  ## later re-emission (e.g. a captured `typed` fragment expanded more than once)
+  ## can be detected as a redefinition rather than silently miscompiled.
+  for s in c.currentScope.symbols:
+    if s.kind in {skVar, skLet, skForVar} and {sfGenSym, sfWasGenSym} * s.flags == {}:
+      c.shadowDiscardedDefs.incl s.id
+
 proc closeShadowScope*(c: PContext) =
   ## closes the shadow scope, but doesn't merge any of the symbols
   ## Does not check for unused symbols or missing forward decls since a macro

compiler/nilcheck.nim

@@ -183,12 +183,6 @@ func `<`*(a: ExprIndex, b: ExprIndex): bool =
 func `<=`*(a: ExprIndex, b: ExprIndex): bool =
   a.int16 <= b.int16
 
-func `>`*(a: ExprIndex, b: ExprIndex): bool =
-  a.int16 > b.int16
-
-func `>=`*(a: ExprIndex, b: ExprIndex): bool =
-  a.int16 >= b.int16
-
 func `==`*(a: ExprIndex, b: ExprIndex): bool =
   a.int16 == b.int16
 

compiler/options.nim

@@ -265,6 +265,11 @@ type
     typedescFieldAccess
       ## Allow typedesc field access on object/tuple types outside of
       ## typeof context.
+    injectedSymbolRedefinition
+      ## Allow a template to inject a symbol *definition* that is then emitted
+      ## more than once (e.g. a `typed` argument captured by a `{.dirty.}`
+      ## template and re-emitted). This is a redefinition and rejected by
+      ## default; enabling this restores the old, unsound behavior. See #25693.
 
   SymbolFilesOption* = enum
     disabledSf, writeOnlySf, readOnlySf, v2Sf, stressTest

compiler/parser.nim

@@ -2241,14 +2241,17 @@ proc parseTypeClassParam(p: var Parser): PNode =
 
 proc parseTypeClass(p: var Parser): PNode =
   #| conceptParam = ('var' | 'out' | 'ptr' | 'ref' | 'static' | 'type')? symbol
-  #| conceptDecl = 'concept' conceptParam ^* ',' (pragma)? ('of' typeDesc ^* ',')?
+  #| conceptDecl = 'concept' (conceptParam ^* ',' (pragma)?)? ('of' typeDesc ^* ',')?
   #|               &IND{>} stmt
   result = newNodeP(nkTypeClassTy, p)
   getTok(p)
   if p.tok.tokType == tkComment:
     skipComment(p, result)
 
-  if p.tok.indent < 0:
+  if p.tok.tokType == tkOf and p.tok.indent < 0:
+    # new-styled `concept of A, B` on the same line as `concept`
+    result.add(p.emptyNode)
+  elif p.tok.indent < 0:
     var args = newNodeP(nkArgList, p)
     result.add(args)
     args.add(p.parseTypeClassParam)
@@ -2274,9 +2277,10 @@ proc parseTypeClass(p: var Parser): PNode =
     result.add(p.emptyNode)
   if p.tok.tokType == tkComment:
     skipComment(p, result)
-  # an initial IND{>} HAS to follow:
+  # an initial IND{>} HAS to follow, unless this concept inherits requirements:
   if not realInd(p):
-    if result.isNewStyleConcept:
+    let hasParents = result[2].kind != nkEmpty
+    if result.isNewStyleConcept and not hasParents:
       parMessage(p, "routine expected, but found '$1' (empty new-styled concepts are not allowed)", p.tok)
     result.add(p.emptyNode)
   else:

compiler/sem.nim

@@ -247,6 +247,26 @@ proc newSymG*(kind: TSymKind, n: PNode, c: PContext): PSym =
     if result.kind notin {kind, skTemp}:
       localError(c.config, n.info, "cannot use symbol of kind '$1' as a '$2'" %
         [result.kind.toHumanStr, kind.toHumanStr])
+    # bug #25693: a local declared inside a template/macro operand (recorded in
+    # `shadowDiscardedDefs`) can be captured by a `{.dirty.}` template and
+    # re-emitted as a definition more than once. The first emission keeps the
+    # original symbol (so a leaked dirty-template name still resolves); every
+    # later emission gets a fresh copy, so distinct emissions don't share one
+    # symbol - which the destructor/liveness analysis would otherwise miscompile.
+    # Unlike a plain redefinition check this is control-flow agnostic, so the
+    # common "emit a `typed` body in several mutually-exclusive branches" pattern
+    # keeps working. gensym'ed locals (and ones derived from a gensym name) are
+    # excluded: the gensym machinery already keeps their names unique, and a
+    # fresh copy would reuse the unique name and clash in the same scope.
+    if kind in {skVar, skLet, skForVar} and
+        {sfGenSym, sfWasGenSym} * result.flags == {} and
+        result.id in c.shadowDiscardedDefs:
+      if containsOrIncl(c.realizedDefs, result.id):
+        let fresh = copySym(result, c.idgen)
+        fresh.ast = result.ast
+        put(c.p, result, fresh)
+        c.hasSymRedefs = true
+        result = fresh
     when false:
       if sfGenSym in result.flags and result.kind notin {skTemplate, skMacro, skParam}:
         # declarative context, so produce a fresh gensym:

compiler/semdata.nim

@@ -189,6 +189,18 @@ type
     inTypeofContext*: int
 
     semAsgnOpr*: proc (c: PContext; n: PNode; k: TNodeKind): PNode {.nimcall.}
+    shadowDiscardedDefs*: IntSet
+      # ids of local symbols that were declared inside a template/macro operand's
+      # shadow scope and then discarded; re-emitting such a symbol as a
+      # definition gives a fresh copy so distinct emissions don't share a symbol.
+      # See bug #25693 and `rememberShadowDefs`.
+    realizedDefs*: IntSet
+      # ids from `shadowDiscardedDefs` already realized once; the first emission
+      # keeps the original symbol (so leaked dirty-template names still resolve),
+      # later emissions get a fresh copy.
+    hasSymRedefs*: bool
+      # set once a redefinition mapping has been installed; makes `getGenSym`
+      # consult the proc-con mapping for non-gensym symbols too.
 
   TBorrowState* = enum
     bsNone, bsReturnNotMatch, bsNoDistinct, bsGeneric, bsNotSupported, bsMatch
@@ -281,7 +293,10 @@ proc get*(p: PProcCon; key: PSym): PSym =
   result = p.mapping.getOrDefault(key.itemId)
 
 proc getGenSym*(c: PContext; s: PSym): PSym =
-  if sfGenSym notin s.flags: return s
+  # `c.hasSymRedefs` additionally routes ordinary (non-gensym) symbols through
+  # the mapping so a re-emitted definition can redirect them to its fresh copy,
+  # see bug #25693 and `newSymG`.
+  if sfGenSym notin s.flags and not c.hasSymRedefs: return s
   var it = c.p
   while it != nil:
     result = get(it, s)
@@ -343,6 +358,8 @@ proc newContext*(graph: ModuleGraph; module: PSym): PContext =
     userPragmas: initStrTable(),
     generics: @[],
     unknownIdents: initIntSet(),
+    shadowDiscardedDefs: initIntSet(),
+    realizedDefs: initIntSet(),
     cache: graph.cache,
     graph: graph,
     signatures: initStrTable(),

compiler/semgnrc.nim

@@ -129,7 +129,14 @@ proc semGenericStmtSymbol(c: PContext, n: PNode, s: PSym,
           result.typ = nil
     onUse(n.info, s)
   of skParam:
-    result = n
+    if s.owner == c.p.owner:
+      # Parameters of the routine currently being semchecked stay as local
+      # identifiers
+      result = n
+    else:
+      # Preserve captured outer parameters so nested generic procs can still
+      # see them after the generic pre-pass.
+      result = newSymNode(s, n.info)
     onUse(n.info, s)
   of skType:
     if (s.typ != nil) and

compiler/sempass2.nim

@@ -497,6 +497,26 @@ proc addRaiseEffect(a: PEffects, e, comesFrom: PNode) =
     if not isDefectException(e.typ):
       throws(a.exc, e, comesFrom)
 
+proc addRaiseEffectsFromExpr(a: PEffects, e, comesFrom: PNode) =
+  if e.isNil:
+    return
+  let x = skipConvCastAndClosure(e)
+  case x.kind
+  of nkStmtList, nkStmtListExpr, nkBlockStmt, nkBlockExpr:
+    if x.len > 0:
+      addRaiseEffectsFromExpr(a, x.lastSon, comesFrom)
+  of nkIfExpr, nkIfStmt:
+    for branch in items(x):
+      if branch.len > 0:
+        addRaiseEffectsFromExpr(a, branch.lastSon, comesFrom)
+  of nkCaseStmt:
+    for i in 1..<x.len:
+      let branch = x[i]
+      if branch.len > 0:
+        addRaiseEffectsFromExpr(a, branch.lastSon, comesFrom)
+  else:
+    addRaiseEffect(a, x, x)
+
 proc addTag(a: PEffects, e, comesFrom: PNode) =
   var aa = a.tags
   for i in 0..<aa.len:
@@ -1208,6 +1228,7 @@ type
     enforcedGcSafety, enforceNoSideEffects: bool
     oldExc, oldTags, oldForbids: int
     exc, tags, forbids: PNode
+    excSource, tagsSource, forbidsSource: PNode
 
 proc createBlockContext(tracked: PEffects): PragmaBlockContext =
   var oldForbidsLen = 0
@@ -1230,17 +1251,18 @@ proc unapplyBlockContext(tracked: PEffects; bc: PragmaBlockContext) =
     # anything about 'raises' in the 'cast' at all. Same applies for 'tags'.
     setLen(tracked.exc.sons, bc.oldExc)
     for e in bc.exc:
-      addRaiseEffect(tracked, e, e)
+      addRaiseEffect(tracked, e, if bc.excSource != nil: bc.excSource else: e)
   if bc.tags != nil:
     setLen(tracked.tags.sons, bc.oldTags)
     for t in bc.tags:
-      addTag(tracked, t, t)
+      addTag(tracked, t, if bc.tagsSource != nil: bc.tagsSource else: t)
   if bc.forbids != nil:
     setLen(tracked.forbids.sons, bc.oldForbids)
     for t in bc.forbids:
-      addNotTag(tracked, t, t)
+      addNotTag(tracked, t, if bc.forbidsSource != nil: bc.forbidsSource else: t)
 
-proc castBlock(tracked: PEffects, pragma: PNode, bc: var PragmaBlockContext) =
+proc castBlock(tracked: PEffects, castPragma: PNode, bc: var PragmaBlockContext) =
+  let pragma = castPragma[1]
   case whichPragma(pragma)
   of wGcSafe:
     bc.enforcedGcSafety = true
@@ -1253,6 +1275,7 @@ proc castBlock(tracked: PEffects, pragma: PNode, bc: var PragmaBlockContext) =
     else:
       bc.tags = newNodeI(nkArgList, pragma.info)
       bc.tags.add n
+    bc.tagsSource = castPragma
   of wForbids:
     let n = pragma[1]
     if n.kind in {nkCurly, nkBracket}:
@@ -1260,6 +1283,7 @@ proc castBlock(tracked: PEffects, pragma: PNode, bc: var PragmaBlockContext) =
     else:
       bc.forbids = newNodeI(nkArgList, pragma.info)
       bc.forbids.add n
+    bc.forbidsSource = castPragma
   of wRaises:
     let n = pragma[1]
     if n.kind in {nkCurly, nkBracket}:
@@ -1267,6 +1291,7 @@ proc castBlock(tracked: PEffects, pragma: PNode, bc: var PragmaBlockContext) =
     else:
       bc.exc = newNodeI(nkArgList, pragma.info)
       bc.exc.add n
+    bc.excSource = castPragma
   of wUncheckedAssign:
     discard "handled in sempass1"
   else:
@@ -1303,6 +1328,8 @@ proc allowCStringConv(n: PNode): bool =
 
 proc track(tracked: PEffects, n: PNode) =
   case n.kind
+  of nkTypeOfExpr:
+    discard "typeof() never evaluates its operand; not a definite-assignment use"
   of nkSym:
     useVar(tracked, n)
     if n.sym.typ != nil and tfHasAsgn in n.sym.typ.flags:
@@ -1319,7 +1346,7 @@ proc track(tracked: PEffects, n: PNode) =
     if n[0].kind != nkEmpty:
       n[0].info = n.info
       #throws(tracked.exc, n[0])
-      addRaiseEffect(tracked, n[0], n)
+      addRaiseEffectsFromExpr(tracked, n[0], n)
       for i in 0..<n.safeLen:
         track(tracked, n[i])
       createTypeBoundOps(tracked, n[0].typ, n.info)
@@ -1520,7 +1547,7 @@ proc track(tracked: PEffects, n: PNode) =
       of wNoSideEffect:
         bc.enforceNoSideEffects = true
       of wCast:
-        castBlock(tracked, pragmaList[i][1], bc)
+        castBlock(tracked, pragmaList[i], bc)
       else:
         discard
     applyBlockContext(tracked, bc)

compiler/semstmts.nim

@@ -2642,6 +2642,11 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
       elif s.name.s == "()" and callOperator notin c.features:
         localError(c.config, n.info, "the overloaded " & s.name.s &
           " operator has to be enabled with {.experimental: \"callOperator\".}")
+    elif sfImportc notin s.flags and (s.name.s == ">" or s.name.s == ">=" or s.name.s == "!="):
+      # ignore imported procs as these operators in backend language might have different semantics
+      let op1 = if s.name.s == "!=": "==" elif s.name.s == ">": "<" else: "<="
+      message(c.config, n.info, warnInvalidCmpOp, "define `" & op1 & "` instead of `" & s.name.s & "` to implement user defined comparison operator. " &
+              "it allows you to use `" & s.name.s & "` automatically.")
 
   if sfBorrow in s.flags and c.config.cmd notin cmdDocLike:
     result[bodyPos] = c.graph.emptyNode

compiler/sigmatch.nim

@@ -791,8 +791,10 @@ proc procParamTypeRel(c: var TCandidate; f, a: PType): TTypeRelation =
     # different C types (size_t vs unsigned long long).
     let fCheck = concreteType(c, f)
     let aCheck = concreteType(c, a)
+    # Note that `result` is equal; now check whether they have the same
+    # backend type.
     if fCheck != nil and aCheck != nil and
-        not sameBackendTypePickyAliases(fCheck, aCheck):
+      not sameBackendTypePickyAliases(fCheck, aCheck, {IgnoreFlags}):
       result = isNone
 
   if result <= isSubrange or inconsistentVarTypes(f, a):
@@ -1757,6 +1759,21 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
       let ff = last(f)
       if ff != nil:
         result = typeRel(c, ff, a, flags)
+      if result == isNone and a.kind == tyGenericInst and trBindGenericParam in flags:
+        var depth = -1
+        # Generic-parameter constraints like `F: Future` can miss in `last(f)`
+        # when the actual type inherits from a concrete generic instantiation.
+        # Keep this fallback scoped to generic-parameter matching so typedesc
+        # overloads such as `type Future[T]` still prefer more specific
+        # descendants like `InternalRaisesFuture[T, E]`.
+        if isGenericSubtype(c, a, f, depth, f) and depth > 0:
+          var askip = skippedNone
+          let aobj = a.skipToObject(askip)
+          if aobj != nil and tfFinal notin aobj.flags:
+            # Keep overload ranking consistent with other inheritance-based
+            # matches: deeper descendants are slightly worse candidates.
+            inc c.inheritancePenalty, depth + int(c.inheritancePenalty < 0)
+          result = isGeneric
   of tyGenericInvocation:
     var x = a.skipGenericAlias
     if x.kind == tyGenericParam and x.len > 0:
@@ -2471,6 +2488,10 @@ proc paramTypesMatchAux(m: var TCandidate, f, a: PType,
       return arg
     elif f.kind == tyStatic and arg.typ.n != nil:
       return arg.typ.n
+    elif f.kind == tyUntyped:
+      # bug #25693: a different overload candidate may have sem-checked the
+      # operand and left symbols behind; templates expect the pristine AST.
+      return argOrig
     else:
       return argSemantized # argOrig
 
@@ -2849,6 +2870,7 @@ proc matchesAux(c: PContext, n, nOrig: PNode, m: var TCandidate, marker: var Int
     if m.calleeSym != nil and m.calleeSym.kind notin {skTemplate, skMacro}:
       c.mergeShadowScope
     else:
+      c.rememberShadowDefs
       c.closeShadowScope
     m.state = csNoMatch
     m.firstMismatch.arg = a
@@ -2905,7 +2927,10 @@ proc matchesAux(c: PContext, n, nOrig: PNode, m: var TCandidate, marker: var Int
           setSon(m.call, formal.position + 1, container)
         else:
           incrIndexType(container.typ)
-        container.add n[a]
+        # bug #25693: like the scalar `tyUntyped` case in `paramTypesMatchAux`,
+        # a previous overload candidate may have sem-checked the operand in
+        # place; templates/macros expect the pristine AST, so use `nOrig`.
+        container.add nOrig[a]
     elif n[a].kind == nkExprEqExpr:
       # named param
       m.firstMismatch.kind = kUnknownNamedParam
@@ -3004,7 +3029,8 @@ proc matchesAux(c: PContext, n, nOrig: PNode, m: var TCandidate, marker: var Int
             setSon(m.call, formal.position + 1, container)
           else:
             incrIndexType(container.typ)
-          container.add n[a]
+          # bug #25693: see the leading isVarargsUntyped branch above.
+          container.add nOrig[a]
         else:
           m.baseTypeMatch = false
           m.typedescMatched = false
@@ -3056,6 +3082,7 @@ proc matchesAux(c: PContext, n, nOrig: PNode, m: var TCandidate, marker: var Int
     if m.state == csMatch and not (m.calleeSym != nil and m.calleeSym.kind in {skTemplate, skMacro}):
       c.mergeShadowScope
     else:
+      c.rememberShadowDefs
       c.closeShadowScope
 
     inc a

compiler/spawn.nim

@@ -10,7 +10,7 @@
 ## This module implements threadpool's ``spawn``.
 
 import ast, types, idents, magicsys, msgs, options, modulegraphs,
-  lowerings, liftdestructors, renderer
+  lowerings, liftdestructors, renderer, trees
 from trees import getMagic, getRoot
 
 proc callProc(a: PNode): PNode =
@@ -53,6 +53,24 @@ proc typeNeedsNoDeepCopy(t: PType): bool =
   if t.kind in {tyVar, tyLent, tySequence}: t = t.elementType
   result = not containsGarbageCollectedRef(t)
 
+proc newSpawnMoveStmt(g: ModuleGraph; idgen: IdGenerator; le, ri: PNode): PNode =
+  let op = getAttachedOp(g, ri.typ.skipTypes({tyGenericInst, tyAlias, tyVar, tySink}), attachedWasMoved)
+  if op != nil and sfOverridden in op.flags:
+    result = newNodeI(nkStmtList, le.info)
+    result.add newFastAsgnStmt(le, ri)
+
+    let wasMovedCall = newNodeI(nkCall, ri.info)
+    wasMovedCall.add newSymNode(op)
+    
+    if op.typ != nil and op.typ.signatureLen > 1 and op.typ.firstParamType.kind != tyVar:
+      wasMovedCall.add ri.skipAddr
+    else:
+      wasMovedCall.add makeAddr(ri.skipAddr, idgen)
+    
+    result.add wasMovedCall
+  else:
+    result = newFastMoveStmt(g, le, ri)
+
 proc addLocalVar(g: ModuleGraph; varSection, varInit: PNode; idgen: IdGenerator; owner: PSym; typ: PType;
                  v: PNode; useShallowCopy=false): PSym =
   result = newSym(skTemp, getIdent(g.cache, genPrefix), idgen, owner, varSection.info,
@@ -68,10 +86,10 @@ proc addLocalVar(g: ModuleGraph; varSection, varInit: PNode; idgen: IdGenerator;
   if varInit != nil:
     if g.config.selectedGC in {gcArc, gcOrc, gcAtomicArc, gcYrc}:
       # inject destructors pass will do its own analysis
-      varInit.add newFastMoveStmt(g, newSymNode(result), v)
+      varInit.add newSpawnMoveStmt(g, idgen, newSymNode(result), v)
     else:
       if useShallowCopy and typeNeedsNoDeepCopy(typ) or optTinyRtti in g.config.globalOptions:
-        varInit.add newFastMoveStmt(g, newSymNode(result), v)
+        varInit.add newSpawnMoveStmt(g, idgen, newSymNode(result), v)
       else:
         let deepCopyCall = newNodeI(nkCall, varInit.info, 3)
         deepCopyCall[0] = newSymNode(getSysMagic(g, varSection.info, "deepCopy", mDeepCopy))

compiler/transf.nim

@@ -22,7 +22,7 @@ import std / tables
 
 import
   options, ast, astalgo, trees, msgs,
-  idents, renderer, types, semfold, magicsys, cgmeth,
+  idents, renderer, types, semfold, magicsys, cgmeth, parampatterns,
   lowerings, liftlocals,
   modulegraphs, lineinfos
 
@@ -90,11 +90,21 @@ proc getCurrOwner(c: PTransf): PSym =
   if c.transCon != nil: result = c.transCon.owner
   else: result = c.module
 
+proc freshOwnedSym(c: PTransf; s, owner: PSym): PNode =
+  # We need to copy the symbol here because we might need to change its owner and
+  # we don't want to mess with the original symbol which might be used in other places.
+  # This can happen for example for iterators which are transformed multiple times when
+  # they are used in different contexts.
+  var fresh = copySym(s, c.idgen)
+  if fresh.kind notin routineKinds:
+    incl(fresh.flagsImpl, sfFromGeneric)
+  setOwner(fresh, owner)
+  result = newSymNode(fresh)
+
 proc newTemp(c: PTransf, typ: PType, info: TLineInfo): PNode =
   let r = newSym(skTemp, getIdent(c.graph.cache, genPrefix), c.idgen, getCurrOwner(c), info)
   r.typ = typ #skipTypes(typ, {tyGenericInst, tyAlias, tySink})
   incl(r.flagsImpl, sfFromGeneric)
-  let owner = getCurrOwner(c)
   result = newSymNode(r)
 
 proc transform(c: PTransf, n: PNode, noConstFold = false): PNode
@@ -185,11 +195,39 @@ proc transformSym(c: PTransf, n: PNode): PNode =
   result = transformSymAux(c, n)
 
 proc freshVar(c: PTransf; v: PSym): PNode =
-  let owner = getCurrOwner(c)
-  var newVar = copySym(v, c.idgen)
-  incl(newVar.flagsImpl, sfFromGeneric)
-  setOwner(newVar, owner)
-  result = newSymNode(newVar)
+  result = freshOwnedSym(c, v, getCurrOwner(c))
+
+proc introduceNewRoutineHeaderSyms(c: PTransf; n: PNode; oldOwner, newOwner: PSym) =
+  # We need to introduce new symbols for the parameters and result of a routine when
+  # we copy it for inlining or closure generation.
+  # Otherwise, we would have multiple nodes referring to the same parameter symbols which
+  # can lead to problems when we need to change the owner of these symbols.
+  case n.kind
+  of nkSym:
+    if n.sym.owner == oldOwner:
+      c.transCon.mapping[n.sym.itemId] = freshOwnedSym(c, n.sym, newOwner)
+  of nkEmpty..pred(nkSym), succ(nkSym)..nkNilLit:
+    discard
+  else:
+    for i in 0..<n.len:
+      introduceNewRoutineHeaderSyms(c, n[i], oldOwner, newOwner)
+
+proc copyRoutineTypeHeader(c: PTransf; oldProc, newProc: PSym) =
+  # We need to copy the routine type header to ensure that
+  # modifications to the newProc do not affect the oldProc.
+  if oldProc.typ != nil and oldProc.typ.kind == tyProc and oldProc.typ.n != nil:
+    newProc.typ = copyType(oldProc.typ, c.idgen, newProc)
+    newProc.typ.n = newNodeI(oldProc.typ.n.kind, oldProc.typ.n.info)
+    if oldProc.typ.n.len > 0:
+      newProc.typ.n.add copyTree(oldProc.typ.n[0])
+      for i in 1..<oldProc.typ.n.len:
+        let oldParam = oldProc.typ.n[i].sym
+        var newParam = getOrDefault(c.transCon.mapping, oldParam.itemId)
+        if newParam == nil:
+          newParam = freshOwnedSym(c, oldParam, newProc)
+          c.transCon.mapping[oldParam.itemId] = newParam
+        doAssert newParam.kind == nkSym
+        newProc.typ.addParam newParam.sym
 
 proc transformVarSection(c: PTransf, v: PNode): PNode =
   result = newTransNode(v)
@@ -338,11 +376,18 @@ proc introduceNewLocalVars(c: PTransf, n: PNode): PNode =
     return n
   of nkLambdaKinds, nkProcDef, nkFuncDef, nkMethodDef, nkConverterDef: # todo optimize nosideeffects?
     result = newTransNode(n)
-    let x = newSymNode(copySym(n[namePos].sym, c.idgen))
-    c.transCon.mapping[n[namePos].sym.itemId] = x
+    let oldProc = n[namePos].sym
+    let x = freshOwnedSym(c, oldProc, oldProc.owner)
+    c.transCon.mapping[oldProc.itemId] = x
+    introduceNewRoutineHeaderSyms(c, n[paramsPos], oldProc, x.sym)
+    if resultPos < n.len and n[resultPos] != nil:
+      introduceNewRoutineHeaderSyms(c, n[resultPos], oldProc, x.sym)
+    copyRoutineTypeHeader(c, oldProc, x.sym)
     result[namePos] = x # we have to copy proc definitions for iters
     for i in 1..<n.len:
       result[i] = introduceNewLocalVars(c, n[i])
+    if x.sym.typ != nil and x.sym.typ.kind == tyProc:
+      result[paramsPos] = x.sym.typ.n
     result[namePos].sym.ast = result
   else:
     result = newTransNode(n)
@@ -675,7 +720,7 @@ type
     paDirectMapping, paFastAsgn, paFastAsgnTakeTypeFromArg
     paVarAsgn, paComplexOpenarray, paViaIndirection
 
-proc putArgInto(arg: PNode, formal: PType): TPutArgInto =
+proc putArgInto(arg: PNode, formal: PType; borrowedFirstArg = false): TPutArgInto =
   # This analyses how to treat the mapping "formal <-> arg" in an
   # inline context.
   if formal.kind == tyTypeDesc: return paDirectMapping
@@ -726,6 +771,13 @@ proc putArgInto(arg: PNode, formal: PType): TPutArgInto =
     if skipTypes(formal, abstractInst).kind in {tyVar, tyLent}: result = paVarAsgn
     else: result = paFastAsgn
 
+  if borrowedFirstArg and result == paDirectMapping and parampatterns.exprRoot(arg) == nil and
+           parampatterns.isAssignable(nil, arg) == arNone:
+    # Inline iterators like `items(array)` borrow from the first argument.
+    # If that argument is just a transient expression, materialize it so the
+    # lifted closure keeps the backing storage alive across yields.
+    result = paFastAsgnTakeTypeFromArg
+
 proc findWrongOwners(c: PTransf, n: PNode) =
   if n.kind == nkVarSection:
     let x = n[0][0]
@@ -824,13 +876,16 @@ proc transformFor(c: PTransf, n: PNode): PNode =
   if iter.kind != skIterator: return result
   # generate access statements for the parameters (unless they are constant)
   pushTransCon(c, newC)
+  let borrowedIterResult =
+    iter.typ != nil and iter.typ.returnType != nil and
+    skipTypes(iter.typ.returnType, abstractInst).kind in {tyLent, tyVar}
   for i in 1..<call.len:
     var arg = transform(c, call[i])
     let ff = skipTypes(iter.typ, abstractInst)
     # can happen for 'nim check':
     if i >= ff.n.len: return result
     var formal = ff.n[i].sym
-    let pa = putArgInto(arg, formal.typ)
+    let pa = putArgInto(arg, formal.typ, borrowedIterResult and i == 1)
     case pa
     of paDirectMapping:
       newC.mapping[formal.itemId] = arg

compiler/types.nim

@@ -1069,9 +1069,10 @@ proc sameBackendTypeIgnoreRange*(x, y: PType): bool =
   c.cmp = dcEqIgnoreDistinct
   result = sameTypeAux(x, y, c)
 
-proc sameBackendTypePickyAliases*(x, y: PType): bool =
+proc sameBackendTypePickyAliases*(x, y: PType, flags: TTypeCmpFlags = {}): bool =
   var c = initSameTypeClosure()
   c.flags.incl {IgnoreTupleFields, IgnoreRangeShallow, PickyCAliases, PickyBackendAliases}
+  c.flags.incl flags
   c.cmp = dcEqIgnoreDistinct
   result = sameTypeAux(x, y, c)
 

compiler/varpartitions.nim

@@ -185,6 +185,9 @@ proc root(v: var Partitions; start: int): int =
 proc potentialMutation(v: var Partitions; s: PSym; level: int; info: TLineInfo) =
   let id = variableId(v, s)
   if id >= 0:
+    # mutated here => alive here: keep aliveEnd in sync so dangerousMutation catches
+    # mutations recorded after the var's last use (e.g. via a call arg). See #25595.
+    v.s[id].aliveEnd = max(v.s[id].aliveEnd, v.abstractTime)
     let r = root(v, id)
     let flags = if s.kind == skParam:
                   if isConstParam(s):

compiler/vmgen.nim

@@ -1842,6 +1842,8 @@ proc genArrAccessOpcode(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode;
   if dest < 0: dest = c.getTemp(n.typ)
   if opc in {opcLdArrAddr, opcLdStrIdxAddr} and gfNodeAddr in flags:
     c.gABC(n, opc, dest, a, b)
+    if c.prc.regInfo[a].kind >= slotTempUnknown:
+      c.prc.regInfo[a].kind = slotTempPerm
   elif needsRegLoad():
     var cc = c.getTemp(n.typ)
     c.gABC(n, opc, cc, a, b)
@@ -1858,6 +1860,8 @@ proc genObjAccessAux(c: PCtx; n: PNode; a, b: int, dest: var TDest; flags: TGenF
   if dest < 0: dest = c.getTemp(n.typ)
   if {gfNodeAddr} * flags != {}:
     c.gABC(n, opcLdObjAddr, dest, a, b)
+    if a < c.prc.regInfo.len and c.prc.regInfo[a].kind >= slotTempUnknown:
+      c.prc.regInfo[a].kind = slotTempPerm
   elif needsRegLoad():
     var cc = c.getTemp(n.typ)
     c.gABC(n, opcLdObj, cc, a, b)

compiler/vtables.nim

@@ -152,6 +152,8 @@ proc sortVTableDispatchers*(g: ModuleGraph) =
         rootItemIdCount.inc(baseType.itemId)
       for idx in 0..<g.methods[bucket].methods.len:
         let obj = g.methods[bucket].methods[idx].typ.firstParamType.skipTypes(skipPtrs)
+        if obj.itemId notin itemTable:
+          itemTable[obj.itemId] = newSeq[PSym](methodIndexLen)
         itemTable[obj.itemId][mIndex] = g.methods[bucket].methods[idx]
 
   for baseType in rootTypeSeq: