From 52bf954ba5e139fb696ada4c65f23bdc7a68864d Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Wed, 23 Aug 2023 18:19:39 +0800
Subject: [PATCH] checkpoint

---
 compiler/ast.nim       |  3 ++-
 compiler/options.nim   |  1 +
 compiler/pipelines.nim |  6 ++---
 compiler/procfind.nim  |  2 +-
 compiler/sem.nim       | 55 ++++++++++++++++++++++++++++++++++++++++++
 compiler/semstmts.nim  | 30 +++++++++++++++++------
 compiler/sigmatch.nim  |  1 +
 tests/forward/t1.nim   | 11 +++++++++
 tests/forward/t2.nim   | 14 +++++++++++
 tests/forward/t3.nim   | 15 ++++++++++++
 tests/options/test.h   |  5 ++++
 11 files changed, 131 insertions(+), 12 deletions(-)
 create mode 100644 tests/forward/t1.nim
 create mode 100644 tests/forward/t2.nim
 create mode 100644 tests/forward/t3.nim
 create mode 100644 tests/options/test.h

diff --git a/compiler/ast.nim b/compiler/ast.nim
index ce5ad0f292..9e60b1abf3 100644
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -231,7 +231,7 @@ type
   TNodeKinds* = set[TNodeKind]
 
 type
-  TSymFlag* = enum    # 51 flags!
+  TSymFlag* = enum    # 52 flags!
     sfUsed,           # read access of sym (for warnings) or simply used
     sfExported,       # symbol is exported from module
     sfFromGeneric,    # symbol is instantiation of a generic; this is needed
@@ -316,6 +316,7 @@ type
     sfByCopy          # param is marked as pass bycopy
     sfMember          # proc is a C++ member of a type
     sfCodegenDecl     # type, proc, global or proc param is marked as codegenDecl
+    sfToplevelDecl
 
   TSymFlags* = set[TSymFlag]
 
diff --git a/compiler/options.nim b/compiler/options.nim
index bda86a5989..bb1eb52d83 100644
--- a/compiler/options.nim
+++ b/compiler/options.nim
@@ -222,6 +222,7 @@ type
     strictDefs,
     strictCaseObjects,
     inferGenericTypes
+    noforwardDecl
 
   LegacyFeature* = enum
     allowSemcheckedAstModification,
diff --git a/compiler/pipelines.nim b/compiler/pipelines.nim
index 8517cd9426..4324b77280 100644
--- a/compiler/pipelines.nim
+++ b/compiler/pipelines.nim
@@ -81,9 +81,9 @@ proc prePass(c: PContext; n: PNode) =
             of nkStrLit, nkRStrLit, nkTripleStrLit:
               try:
                 let feature = parseEnum[Feature](name.strVal)
-                if feature == codeReordering:
-                  c.features.incl feature
-                  c.module.flags.incl sfReorder
+                # if feature == codeReordering:
+                c.features.incl feature
+                c.module.flags.incl sfReorder
               except ValueError:
                 discard
             else:
diff --git a/compiler/procfind.nim b/compiler/procfind.nim
index 0bdb3dae6d..5877a9dac1 100644
--- a/compiler/procfind.nim
+++ b/compiler/procfind.nim
@@ -34,7 +34,7 @@ proc searchForProcAux(c: PContext, scope: PScope, fn: PSym): PSym =
   var it: TIdentIter
   result = initIdentIter(it, scope.symbols, fn.name)
   while result != nil:
-    if result.kind == fn.kind: #and sameType(result.typ, fn.typ, flags):
+    if result.kind == fn.kind and result.typ != nil: #and sameType(result.typ, fn.typ, flags):
       case equalParams(result.typ.n, fn.typ.n)
       of paramsEqual:
         if (sfExported notin result.flags) and (sfExported in fn.flags):
diff --git a/compiler/sem.nim b/compiler/sem.nim
index f69e7a69d0..65ac689cd7 100644
--- a/compiler/sem.nim
+++ b/compiler/sem.nim
@@ -762,6 +762,58 @@ proc isEmptyTree(n: PNode): bool =
   of nkEmpty, nkCommentStmt: result = true
   else: result = false
 
+proc decl(c: PContext, n: PNode, kind: TSymKind): PNode =
+  if n[0].kind == nkIdent:
+    var s = newSym(kind, n[0].ident, c.idgen, getCurrOwner(c), n.info)
+    s.flags.incl sfToplevelDecl
+    # pragmaCallable(c, s, n, allRoutinePragmas)
+
+    result = n
+    if n[^1].kind != nkEmpty:
+      if s.kind in OverloadableSyms:
+        addInterfaceOverloadableSymAt(c, c.currentScope, s)
+      else:
+        addInterfaceDeclAt(c, c.currentScope, s)
+
+    result[0] = newSymNode(s)
+  else:
+    result = n
+
+import reorder
+
+proc semSignature(c: PContext, n: PNode): PNode =
+  case n.kind
+  of nkProcDef:
+    result = decl(c, n, skProc)
+  of nkMethodDef:
+    result = decl(c, n, skMethod)
+  of nkConverterDef:
+    result = decl(c, n, skConverter)
+  of nkMacroDef:
+    result = decl(c, n, skMacro)
+  of nkTemplateDef:
+    result = decl(c, n, skTemplate)
+  of nkIteratorDef:
+    result = decl(c, n, skIterator)
+  of nkIncludeStmt:
+    result = n
+    for i in 0..<n.len:
+      var f = checkModuleName(c.config, n[i])
+      if f != InvalidFileIdx:
+        if containsOrIncl(c.includedFiles, f.int):
+          localError(c.config, n[i].info, "recursive dependency: '$1'" %
+            toMsgFilename(c.config, f))
+        else:
+          let nn = includeModule(c.graph, c.module, f)
+          result = semSignature(c, nn)
+          excl(c.includedFiles, f.int)
+  of nkStmtList:
+    result = copyNode(n)
+    for i in 0..<n.len:
+      result.add semSignature(c, n[i])
+  else:
+    result = n
+
 proc semStmtAndGenerateGenerics(c: PContext, n: PNode): PNode =
   if c.topStmts == 0 and not isImportSystemStmt(c.graph, n):
     if sfSystemModule notin c.module.flags and not isEmptyTree(n):
@@ -775,6 +827,9 @@ proc semStmtAndGenerateGenerics(c: PContext, n: PNode): PNode =
     result = semAllTypeSections(c, n)
   else:
     result = n
+  # if noforwardDecl in c.features:
+  #   debug result
+  result = semSignature(c, result)
   result = semStmt(c, result, {})
   when false:
     # Code generators are lazy now and can deal with undeclared procs, so these
diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index 39c37f4fb2..305a625368 100644
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -1726,6 +1726,7 @@ proc semProcAnnotation(c: PContext, prc: PNode;
                        validPragmas: TSpecialWords): PNode =
   # Mirrored with semVarMacroPragma
   result = nil
+  doAssert prc != nil
   var n = prc[pragmasPos]
   if n == nil or n.kind == nkEmpty: return
   for i in 0..<n.len:
@@ -2175,6 +2176,12 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
   var (proto, comesFromShadowScope) =
       if isAnon: (nil, false)
       else: searchForProc(c, declarationScope, s)
+
+  # if sfToplevelDecl in s.flags and proto != nil:
+  #   # symTabRemove(declarationScope.symbols, proto)
+  #   s.flags.incl proto.flags # copy flags of forward decls
+  #   proto = nil
+
   if proto == nil and sfForward in s.flags and n[bodyPos].kind != nkEmpty:
     ## In cases such as a macro generating a proc with a gensymmed name we
     ## know `searchForProc` will not find it and sfForward will be set. In
@@ -2204,11 +2211,6 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
       # pragma analysis further down.
       s.typ.callConv = lastOptionEntry(c).defaultCC
 
-  if not hasProto and sfGenSym notin s.flags: #and not isAnon:
-    if s.kind in OverloadableSyms:
-      addInterfaceOverloadableSymAt(c, declarationScope, s)
-    else:
-      addInterfaceDeclAt(c, declarationScope, s)
 
   pragmaCallable(c, s, n, validPragmas)
   if not hasProto:
@@ -2218,6 +2220,18 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
     setEffectsForProcType(c.graph, s.typ, n[pragmasPos], s)
   s.typ.flags.incl tfEffectSystemWorkaround
 
+  let isForwards = n[bodyPos].kind == nkEmpty and {sfImportc, sfBorrow, sfError} * s.flags == {} and s.magic == mNone
+  # delay 
+  if ((sfToplevelDecl notin s.flags or
+        {sfImportc, sfBorrow, sfError} * s.flags != {} or
+        s.magic != mNone
+        ) and
+          not hasProto and sfGenSym notin s.flags): #and not isAnon:
+    if s.kind in OverloadableSyms:
+      addInterfaceOverloadableSymAt(c, declarationScope, s)
+    else:
+      addInterfaceDeclAt(c, declarationScope, s)
+
   # To ease macro generation that produce forwarded .async procs we now
   # allow a bit redundancy in the pragma declarations. The rule is
   # a prototype's pragma list must be a superset of the current pragma
@@ -2240,7 +2254,7 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
     onDef(n[namePos].info, s)
 
   if hasProto:
-    if sfForward notin proto.flags and proto.magic == mNone:
+    if sfForward notin proto.flags and sfToplevelDecl notin proto.flags and proto.magic == mNone:
       wrongRedefinition(c, n.info, proto.name.s, proto.info)
     if not comesFromShadowScope:
       excl(proto.flags, sfForward)
@@ -2389,7 +2403,9 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
 proc determineType(c: PContext, s: PSym) =
   if s.typ != nil: return
   #if s.magic != mNone: return
-  #if s.ast.isNil: return
+  # if s.ast.isNil: return
+  if s.ast == nil:
+    debug s
   discard semProcAux(c, s.ast, s.kind, {})
 
 proc semIterator(c: PContext, n: PNode): PNode =
diff --git a/compiler/sigmatch.nim b/compiler/sigmatch.nim
index 7780e53f53..61ad358bf8 100644
--- a/compiler/sigmatch.nim
+++ b/compiler/sigmatch.nim
@@ -2473,6 +2473,7 @@ proc matchesAux(c: PContext, n, nOrig: PNode, m: var TCandidate, marker: var Int
 
   m.state = csMatch # until proven otherwise
   m.firstMismatch = MismatchInfo()
+  doAssert m.callee != nil
   m.call = newNodeIT(n.kind, n.info, m.callee.base)
   m.call.add n[0]
 
diff --git a/tests/forward/t1.nim b/tests/forward/t1.nim
new file mode 100644
index 0000000000..9fee865cef
--- /dev/null
+++ b/tests/forward/t1.nim
@@ -0,0 +1,11 @@
+{.experimental: "noforwardDecl".}
+
+proc bar(x: int) =
+  var s = 1
+  inc s, x
+  foo(s)
+
+proc foo(x: int) =
+  echo x
+
+bar(999)
\ No newline at end of file
diff --git a/tests/forward/t2.nim b/tests/forward/t2.nim
new file mode 100644
index 0000000000..16ee4491e1
--- /dev/null
+++ b/tests/forward/t2.nim
@@ -0,0 +1,14 @@
+{.experimental: "noforwardDecl".}
+
+proc foo(x: int)
+
+proc bar(x: int) =
+  var s = 1
+  inc s, x
+  foo(s)
+
+
+proc foo(x: int) =
+  echo x
+
+bar(999)
\ No newline at end of file
diff --git a/tests/forward/t3.nim b/tests/forward/t3.nim
new file mode 100644
index 0000000000..d813281acf
--- /dev/null
+++ b/tests/forward/t3.nim
@@ -0,0 +1,15 @@
+{.experimental: "noforwardDecl".}
+
+
+proc bar(x: int) =
+  var s = 1
+  inc s, x
+  foo(s)
+
+proc foo(x: int)
+
+
+proc foo(x: int) =
+  echo x
+
+bar(999)
\ No newline at end of file
diff --git a/tests/options/test.h b/tests/options/test.h
new file mode 100644
index 0000000000..6b52034a3f
--- /dev/null
+++ b/tests/options/test.h
@@ -0,0 +1,5 @@
+#pragma once
+#include "nimbase.h"
+struct Foo {
+  int a;
+};