Automatic dereferencing is removed (#20531)

changelog.md

@@ -46,6 +46,8 @@
 - Optional parameters in combination with `: body` syntax (RFC #405) are now opt-in via
   `experimental:flexibleOptionalParams`.
 
+- Automatic dereferencing (experimental feature) is removed.
+
 - The `Math.trunc` polyfill for targeting Internet Explorer was
   previously included in most JavaScript output files.
   Now, it is only included with `-d:nimJsMathTruncPolyfill`.

compiler/options.nim

@@ -195,7 +195,7 @@ type
     ideRecompile, ideChanged, ideType, ideDeclaration
 
   Feature* = enum  ## experimental features; DO NOT RENAME THESE!
-    implicitDeref,
+    implicitDeref, # deadcode; remains here for backwards compatibility
     dotOperators,
     callOperator,
     parallel,

compiler/semcall.nim

@@ -580,27 +580,6 @@ proc semOverloadedCall(c: PContext, n, nOrig: PNode,
               "Non-matching candidates for " & renderTree(n) & "\n" &
               candidates)
     result = semResolvedCall(c, r, n, flags)
-  elif implicitDeref in c.features and canDeref(n):
-    # try to deref the first argument and then try overloading resolution again:
-    #
-    # XXX: why is this here?
-    # it could be added to the long list of alternatives tried
-    # inside `resolveOverloads` or it could be moved all the way
-    # into sigmatch with hidden conversion produced there
-    #
-    n[1] = n[1].tryDeref
-    var r = resolveOverloads(c, n, nOrig, filter, flags, errors, efExplain in flags)
-    if r.state == csMatch: result = semResolvedCall(c, r, n, flags)
-    else:
-      # get rid of the deref again for a better error message:
-      n[1] = n[1][0]
-      #notFoundError(c, n, errors)
-      if efExplain notin flags:
-        # repeat the overload resolution,
-        # this time enabling all the diagnostic output (this should fail again)
-        discard semOverloadedCall(c, n, nOrig, filter, flags + {efExplain})
-      elif efNoUndeclared notin flags:
-        notFoundError(c, n, errors)
   else:
     if efExplain notin flags:
       # repeat the overload resolution,

compiler/semexprs.nim

@@ -932,12 +932,6 @@ proc resolveIndirectCall(c: PContext; n, nOrig: PNode;
                          t: PType): TCandidate =
   initCandidate(c, result, t)
   matches(c, n, nOrig, result)
-  if result.state != csMatch:
-    # try to deref the first argument:
-    if implicitDeref in c.features and canDeref(n):
-      n[1] = n[1].tryDeref
-      initCandidate(c, result, t)
-      matches(c, n, nOrig, result)
 
 proc bracketedMacro(n: PNode): PSym =
   if n.len >= 1 and n[0].kind == nkSym:

doc/manual.md

@@ -1984,10 +1984,6 @@ dereferencing operations for reference types:
   # no need to write n[].data; in fact n[].data is highly discouraged!
   ```
 
-Automatic dereferencing can be performed for the first argument of a routine
-call, but this is an experimental feature and is described [here](
-manual_experimental.html#automatic-dereferencing).
-
 In order to simplify structural type checking, recursive tuples are not valid:
 
   ```nim

doc/manual_experimental.md

@@ -286,29 +286,6 @@ scope. Therefore, the following will *fail to compile:*
 This feature will likely be replaced with a better solution to remove
 the need for forward declarations.
 
-
-Automatic dereferencing
-=======================
-
-Automatic dereferencing is performed for the first argument of a routine call.
-This feature has to be enabled via `{.experimental: "implicitDeref".}`:
-
-  ```nim
-  {.experimental: "implicitDeref".}
-
-  type
-    NodeObj = object
-      # ...
-    Node = ref NodeObj
-
-  proc depth(x: NodeObj): int = ...
-
-  let n = Node()
-  echo n.depth
-  # no need to write n[].depth
-  ```
-
-
 Special Operators
 =================
 

tests/implicit/timplicit.nim

@@ -1,49 +0,0 @@
-discard """
-  output: '''
-1
-2
-3
-4
-2
-88
-timplicit done
-'''
-"""
-
-
-for x in [1, 2, 3, 4]:
-  echo x
-
-
-type
-  TValue* {.pure, final.} = object of RootObj
-    a: int
-  PValue = ref TValue
-  PPValue = ptr PValue
-
-
-var x: PValue
-new x
-var sp: PPValue = addr x
-
-sp.a = 2
-if sp.a == 2: echo 2  # with sp[].a the error is gone
-
-# Test the new auto-deref a little
-
-{.experimental.}
-
-proc p(x: var int; y: int) = x += y
-
-block:
-  var x: ref int
-  new(x)
-
-  x.p(44)
-
-  var indirect = p
-  x.indirect(44)
-
-  echo x[]
-
-  echo "timplicit done"

tests/objects/tobject.nim

@@ -57,3 +57,18 @@ block: # bug #14698
     x1: int
     x3: seq[int]
   doAssert t[].sizeof == Foo1.sizeof
+
+# bug #147
+type
+  TValue* {.pure, final.} = object of RootObj
+    a: int
+  PValue = ref TValue
+  PPValue = ptr PValue
+
+
+var x: PValue
+new x
+var sp: PPValue = addr x
+
+sp.a = 2
+doAssert sp.a == 2