From 6f5acd211cef377d8f460d0e80611cb5ba2f4422 Mon Sep 17 00:00:00 2001
From: Timothee Cour <timothee.cour2@gmail.com>
Date: Sat, 28 Aug 2021 17:41:13 -0700
Subject: [PATCH] fix for IC

---
 compiler/ast.nim      | 6 +++++-
 compiler/commands.nim | 3 ++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/compiler/ast.nim b/compiler/ast.nim
index b3f37f0858a1e..5893a5671612a 100644
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -997,11 +997,15 @@ type Gconfig = object
   # we put comments in a side channel to avoid increasing `sizeof(TNode)`, which
   # reduces memory usage given that `PNode` is the most allocated type by far.
   comments: Table[int, string] # nodeId => comment
+  useIc*: bool
 
 var gconfig {.threadvar.}: Gconfig
 
+proc setUseIc*(useIc: bool) = gconfig.useIc = useIc
+
 proc comment*(n: PNode): string =
-  if nfHasComment in n.flags:
+  if nfHasComment in n.flags and not gconfig.useIc:
+    # IC doesn't track comments, see `packed_ast`, so this could fail
     result = gconfig.comments[n.nodeId]
 
 proc `comment=`*(n: PNode, a: string) =
diff --git a/compiler/commands.nim b/compiler/commands.nim
index 82e9081525b17..079717862d8dc 100644
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -8,7 +8,7 @@
 #
 
 # This module handles the parsing of command line arguments.
-
+from ast import setUseIc
 
 # We do this here before the 'import' statement so 'defined' does not get
 # confused with 'TGCMode.gcMarkAndSweep' etc.
@@ -862,6 +862,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
       of "v2": conf.symbolFiles = v2Sf
       of "stress": conf.symbolFiles = stressTest
       else: localError(conf, info, "invalid option for --incremental: " & arg)
+    setUseIc(conf.symbolFiles != disabledSf)
   of "skipcfg":
     processOnOffSwitchG(conf, {optSkipSystemConfigFile}, arg, pass, info)
   of "skipprojcfg":