remove {.this.} pragma, deprecated since 0.19 (#20201)

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

changelog.md

@@ -29,6 +29,7 @@
 
 - `nimPreviewDotLikeOps` is going to be removed or deprecated.
 
+- The `{.this.}` pragma, deprecated since 0.19, has been removed.
 - `nil` is no longer a valid value for distinct pointer types.
 
 ## Standard library additions and changes

compiler/ast.nim

@@ -333,7 +333,6 @@ const
   sfWrittenTo* = sfBorrow             # param is assigned to
   sfEscapes* = sfProcvar              # param escapes
   sfBase* = sfDiscriminant
-  sfIsSelf* = sfOverriden             # param is 'self'
   sfCustomPragma* = sfRegister        # symbol is custom pragma template
 
 const

compiler/pragmas.nim

@@ -1216,15 +1216,6 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
         if not isTopLevel(c):
           localError(c.config, n.info, "'experimental' pragma only valid as toplevel statement or in a 'push' environment")
         processExperimental(c, it)
-      of wThis:
-        if it.kind in nkPragmaCallKinds and it.len == 2:
-          c.selfName = considerQuotedIdent(c, it[1])
-          message(c.config, n.info, warnDeprecated, "'.this' pragma is deprecated")
-        elif it.kind == nkIdent or it.len == 1:
-          c.selfName = getIdent(c.cache, "self")
-          message(c.config, n.info, warnDeprecated, "'.this' pragma is deprecated")
-        else:
-          localError(c.config, it.info, "'this' pragma is allowed to have zero or one arguments")
       of wNoRewrite:
         noVal(c, it)
       of wBase:

compiler/semcall.nim

@@ -374,22 +374,6 @@ proc resolveOverloads(c: PContext, n, orig: PNode,
 
   let overloadsState = result.state
   if overloadsState != csMatch:
-    if c.p != nil and c.p.selfSym != nil:
-      # we need to enforce semchecking of selfSym again because it
-      # might need auto-deref:
-      var hiddenArg = newSymNode(c.p.selfSym)
-      hiddenArg.typ = nil
-      n.sons.insert(hiddenArg, 1)
-      orig.sons.insert(hiddenArg, 1)
-
-      pickBest(f)
-
-      if result.state != csMatch:
-        n.sons.delete(1)
-        orig.sons.delete(1)
-        excl n.flags, nfExprCall
-      else: return
-
     if nfDotField in n.flags:
       internalAssert c.config, f.kind == nkIdent and n.len >= 2
 

compiler/semdata.nim

@@ -36,7 +36,6 @@ type
                                  # statements
     owner*: PSym              # the symbol this context belongs to
     resultSym*: PSym          # the result symbol (if we are in a proc)
-    selfSym*: PSym            # the 'self' symbol (if available)
     nestedLoopCounter*: int   # whether we are in a loop or not
     nestedBlockCounter*: int  # whether we are in a block or not
     next*: PProcCon           # used for stacking procedure contexts
@@ -149,7 +148,6 @@ type
     inParallelStmt*: int
     instTypeBoundOp*: proc (c: PContext; dc: PSym; t: PType; info: TLineInfo;
                             op: TTypeAttachedOp; col: int): PSym {.nimcall.}
-    selfName*: PIdent
     cache*: IdentCache
     graph*: ModuleGraph
     signatures*: TStrTable

compiler/semexprs.nim

@@ -1283,33 +1283,6 @@ proc semSym(c: PContext, n: PNode, sym: PSym, flags: TExprFlags): PNode =
     result = newSymNode(s, n.info)
     result.typ = makeTypeDesc(c, s.typ)
   of skField:
-    var p = c.p
-    while p != nil and p.selfSym == nil:
-      p = p.next
-    if p != nil and p.selfSym != nil:
-      var ty = skipTypes(p.selfSym.typ, {tyGenericInst, tyVar, tyLent, tyPtr, tyRef,
-                                         tyAlias, tySink, tyOwned})
-      while tfBorrowDot in ty.flags: ty = ty.skipTypes({tyDistinct, tyGenericInst, tyAlias})
-      var check: PNode = nil
-      if ty.kind == tyObject:
-        while true:
-          check = nil
-          let f = lookupInRecordAndBuildCheck(c, n, ty.n, s.name, check)
-          if f != nil and fieldVisible(c, f):
-            # is the access to a public field or in the same module or in a friend?
-            doAssert f == s
-            markUsed(c, n.info, f)
-            onUse(n.info, f)
-            result = newNodeIT(nkDotExpr, n.info, f.typ)
-            result.add makeDeref(newSymNode(p.selfSym))
-            result.add newSymNode(f) # we now have the correct field
-            if check != nil:
-              check[0] = result
-              check.typ = result.typ
-              result = check
-            return result
-          if ty[0] == nil: break
-          ty = skipTypes(ty[0], skipPtrs)
     # old code, not sure if it's live code:
     markUsed(c, n.info, s)
     onUse(n.info, s)

compiler/seminst.nim

@@ -28,32 +28,13 @@ proc addObjFieldsToLocalScope(c: PContext; n: PNode) =
       # it is not an error to shadow fields via parameters
   else: discard
 
-proc rawPushProcCon(c: PContext, owner: PSym) =
+proc pushProcCon*(c: PContext; owner: PSym) =
   var x: PProcCon
   new(x)
   x.owner = owner
   x.next = c.p
   c.p = x
 
-proc rawHandleSelf(c: PContext; owner: PSym) =
-  const callableSymbols = {skProc, skFunc, skMethod, skConverter, skIterator, skMacro}
-  if c.selfName != nil and owner.kind in callableSymbols and owner.typ != nil:
-    let params = owner.typ.n
-    if params.len > 1:
-      let arg = params[1].sym
-      if arg.name.id == c.selfName.id:
-        c.p.selfSym = arg
-        arg.flags.incl sfIsSelf
-        var t = c.p.selfSym.typ.skipTypes(abstractPtrs)
-        while t.kind == tyObject:
-          addObjFieldsToLocalScope(c, t.n)
-          if t[0] == nil: break
-          t = t[0].skipTypes(skipPtrs)
-
-proc pushProcCon*(c: PContext; owner: PSym) =
-  rawPushProcCon(c, owner)
-  rawHandleSelf(c, owner)
-
 const
   errCannotInstantiateX = "cannot instantiate: '$1'"
 
@@ -377,7 +358,7 @@ proc generateInstance(c: PContext, fn: PSym, pt: TIdTable,
     addDecl(c, s)
     entry.concreteTypes[i] = s.typ
     inc i
-  rawPushProcCon(c, result)
+  pushProcCon(c, result)
   instantiateProcType(c, pt, result, info)
   for j in 1..<result.typ.len:
     entry.concreteTypes[i] = result.typ[j]
@@ -392,7 +373,6 @@ proc generateInstance(c: PContext, fn: PSym, pt: TIdTable,
     # a ``compiles`` context but this is the lesser evil. See
     # bug #1055 (tevilcompiles).
     #if c.compilesContextId == 0:
-    rawHandleSelf(c, result)
     entry.compilesId = c.compilesContextId
     addToGenericProcCache(c, fn, entry)
     c.generics.add(makeInstPair(fn, entry))

tests/destructor/tcustomstrings.nim

@@ -8,8 +8,6 @@ after 20 20'''
 joinable: false
 """
 
-{.this: self.}
-
 type
   mystring = object
     len, cap: int
@@ -51,7 +49,7 @@ proc resize(self: var mystring) =
   if self.cap == 0: self.cap = 8
   else: self.cap = (self.cap * 3) shr 1
   if self.data == nil: inc allocCount
-  self.data = cast[type(data)](realloc(self.data, self.cap + 1))
+  self.data = cast[type(self.data)](realloc(self.data, self.cap + 1))
 
 proc add*(self: var mystring; c: char) =
   if self.len >= self.cap: resize(self)
@@ -60,17 +58,17 @@ proc add*(self: var mystring; c: char) =
   inc self.len
 
 proc ensure(self: var mystring; newLen: int) =
-  if newLen >= cap:
-    cap = max((cap * 3) shr 1, newLen)
-    if cap > 0:
-      if data == nil: inc allocCount
-      data = cast[type(data)](realloc(data, cap + 1))
+  if newLen >= self.cap:
+    self.cap = max((self.cap * 3) shr 1, newLen)
+    if self.cap > 0:
+      if self.data == nil: inc allocCount
+      self.data = cast[type(self.data)](realloc(self.data, self.cap + 1))
 
 proc add*(self: var mystring; y: mystring) =
-  let newLen = len + y.len
+  let newLen = self.len + y.len
   ensure(self, newLen)
-  copyMem(addr data[len], y.data, y.data.len + 1)
-  len = newLen
+  copyMem(addr self.data[self.len], y.data, y.data.len + 1)
+  self.len = newLen
 
 proc create*(lit: string): mystring =
   let newLen = lit.len

tests/misc/tupcomingfeatures.nim

@@ -1,35 +0,0 @@
-discard """
-  output: '''0 -2 0
-0 -2'''
-"""
-
-{.this: self.}
-
-type
-  Foo = object
-    a, b, x: int
-
-proc yay(self: Foo) =
-  echo a, " ", b, " ", x
-
-proc footest[T](self: var Foo, a: T) =
-  b = 1+a
-  yay()
-
-proc nongeneric(self: Foo) =
-  echo a, " ", b
-
-var ff: Foo
-footest(ff, -3)
-ff.nongeneric
-
-{.experimental.}
-using
-  c: Foo
-  x, y: int
-
-proc usesSig(c) =
-  echo "yummy"
-
-proc foobar(c, y) =
-  echo "yay"

tests/overload/tselfderef.nim

@@ -1,20 +0,0 @@
-discard """
-action: compile
-"""
-
-# bug #4671
-{.experimental.}
-{.this: self.}
-type
-  SomeObj = object
-    f: int
-
-proc f(num: int) =
-  discard
-
-var intptr: ptr int
-intptr.f() # compiles fine
-
-proc doSomething(self: var SomeObj) =
-  var pint: ptr int
-  pint.f() # Error: expression '.(pint, "f")' cannot be called

tests/usingstmt/tthis.nim

@@ -1,15 +0,0 @@
-
-# bug #4177
-
-type
-  Parent = object of RootObj
-    parentField: int
-  Child = object of Parent
-    childField: int
-
-{.this: self.}
-proc sumFields(self: Child): int =
-  result = parentField + childField # Error: undeclared identifier: 'parentField'
-
-proc sumFieldsWorks(self: Child): int =
-  result = self.parentField + childField

tests/usingstmt/tusingstmt.nim

@@ -0,0 +1,16 @@
+type
+  Foo = object
+
+using
+  c: Foo
+  x, y: int
+
+proc usesSig(c) = discard
+
+proc foobar(c, y) = discard
+
+usesSig(Foo())
+foobar(Foo(), 123)
+doAssert not compiles(usesSig(123))
+doAssert not compiles(foobar(Foo(), Foo()))
+doAssert not compiles(foobar(123, 123))