fix typedesc field access

changelog.md

@@ -12,6 +12,10 @@ rounding guarantees (via the
   avoid conflicts with `system.default`, so named argument usage for this
   parameter like `getOrDefault(..., default = ...)` will have to be changed.
 
+- Typedesc field access on object/tuple types (e.g. `Foo[int].val`) is now
+  restricted to `typeof` context. Use `--legacy:typedescFieldAccess` to restore
+  the previous behavior of allowing it outside `typeof`.
+
 - With `-d:nimPreviewCheckedClose`, the `close` function in the `std/syncio` module now raises an IO exception in case of an error.
 
 - Unknown warnings and hints now gives warnings `warnUnknownNotes` instead of

compiler/options.nim

@@ -262,6 +262,9 @@ type
     procParamTypeBackendAliases
       ## Keep the old proc type compatibility rules that ignore backend
       ## c type aliases.
+    typedescFieldAccess
+      ## Allow typedesc field access on object/tuple types outside of
+      ## typeof context.
 
   SymbolFilesOption* = enum
     disabledSf, writeOnlySf, readOnlySf, v2Sf, stressTest

compiler/semexprs.nim

@@ -1500,7 +1500,8 @@ proc tryReadingTypeField(c: PContext, n: PNode, i: PIdent, ty: PType): PNode =
       markUsed(c, n.info, f)
       onUse(n.info, f)
   of tyObject, tyTuple:
-    if ty.n != nil and ty.n.kind == nkRecList:
+    if (c.inTypeofContext > 0 or typedescFieldAccess in c.config.legacyFeatures) and
+        ty.n != nil and ty.n.kind == nkRecList:
       let field = lookupInRecord(ty.n, i)
       if field != nil:
         n.typ = makeTypeDesc(c, field.typ)

lib/pure/nimprof.nim

@@ -186,7 +186,7 @@ proc writeProfile() {.noconv.} =
     var perProc = initCountTable[string]()
     for i in 0..entries-1:
       var dups = initHashSet[string]()
-      for ii in 0..high(StackTrace.lines):
+      for ii in 0..high(typeof(StackTrace.lines)):
         let procname = profileData[i].st[ii]
         if isNil(procname): break
         let p = $procname
@@ -201,7 +201,7 @@ proc writeProfile() {.noconv.} =
         writeLine(f, "Entry: ", i+1, "/", entries, " Calls: ",
           profileData[i].total // totalCalls, " [sum: ", sum, "; ",
           sum // totalCalls, "]")
-        for ii in 0..high(StackTrace.lines):
+        for ii in 0..high(typeof(StackTrace.lines)):
           let procname = profileData[i].st[ii]
           let filename = profileData[i].st.files[ii]
           if isNil(procname): break

tests/concepts/tmapconcept.nim

@@ -39,7 +39,7 @@ static:
   ok seq[int] is Enumerable[int]
   ok seq[string] is Enumerable
   ok seq[int] is Enumerable[SomeNumber]
-  ok SparseSeq.data is Enumerable
+  ok typeof(SparseSeq.data) is Enumerable
   no seq[string] is Enumerable[int]
   no int is Enumerable
   no int is Enumerable[int]

tests/metatype/ttypedesc3.nim

@@ -48,6 +48,6 @@ type
   Foo[T] = object
     val: T
 
-var x: Foo[int].val
+var x: typeof(Foo[int].val)
 inc(x)
 echo x

tests/metatype/ttypedesc_field_legacy.nim

@@ -0,0 +1,11 @@
+discard """
+  matrix: "--legacy:typedescFieldAccess"
+  output: "4"
+"""
+
+type
+  Foo[T] = object
+    val: T
+
+var x: Foo[int].val = 4
+echo x

tests/pragmas/tcustom_pragma.nim

@@ -330,7 +330,7 @@ TypeDef
     Baz {.expectedAst(typeAst).} = object
       x: string
 
-  static: doAssert Baz.x is string
+  static: doAssert typeof(Baz.x) is string
 
   const procAst = """
 ProcDef