From 9828392df3ac05ead78e14bde7b5865309df8a95 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Fri, 2 Oct 2020 18:53:22 +0200
Subject: [PATCH] implements https://github.com/nim-lang/RFCs/issues/257
 (#15466)

---
 compiler/parampatterns.nim | 2 ++
 compiler/transf.nim        | 7 -------
 compiler/trees.nim         | 7 +++++++
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/compiler/parampatterns.nim b/compiler/parampatterns.nim
index ed8f2c16a3..c2be4b1345 100644
--- a/compiler/parampatterns.nim
+++ b/compiler/parampatterns.nim
@@ -223,6 +223,8 @@ proc isAssignable*(owner: PSym, n: PNode; isUnsafeAddr=false): TAssignableResult
       result = arLValue
     elif isUnsafeAddr and n.sym.kind == skParam:
       result = arLValue
+    elif isUnsafeAddr and n.sym.kind == skConst and dontInlineConstant(n, n.sym.ast):
+      result = arLValue
     elif n.sym.kind in kinds:
       if owner != nil and owner == n.sym.owner and
           sfGlobal notin n.sym.flags:
diff --git a/compiler/transf.nim b/compiler/transf.nim
index 5dd2754145..c8dbf5e041 100644
--- a/compiler/transf.nim
+++ b/compiler/transf.nim
@@ -850,13 +850,6 @@ proc transformExceptBranch(c: PTransf, n: PNode): PNode =
   else:
     result = transformSons(c, n)
 
-proc dontInlineConstant(orig, cnst: PNode): bool {.inline.} =
-  # symbols that expand to a complex constant (array, etc.) should not be
-  # inlined, unless it's the empty array:
-  result = orig.kind == nkSym and
-           cnst.kind in {nkCurly, nkPar, nkTupleConstr, nkBracket} and
-           cnst.len != 0
-
 proc commonOptimizations*(g: ModuleGraph; c: PSym, n: PNode): PNode =
   result = n
   for i in 0..<n.safeLen:
diff --git a/compiler/trees.nim b/compiler/trees.nim
index 473264b526..2cf6b4f679 100644
--- a/compiler/trees.nim
+++ b/compiler/trees.nim
@@ -195,3 +195,10 @@ proc stupidStmtListExpr*(n: PNode): bool =
   for i in 0..<n.len-1:
     if n[i].kind notin {nkEmpty, nkCommentStmt}: return false
   result = true
+
+proc dontInlineConstant*(orig, cnst: PNode): bool {.inline.} =
+  # symbols that expand to a complex constant (array, etc.) should not be
+  # inlined, unless it's the empty array:
+  result = orig.kind == nkSym and
+           cnst.kind in {nkCurly, nkPar, nkTupleConstr, nkBracket} and
+           cnst.len != 0