Fixes incorrect macro stack traces.

compiler/vm.nim

@@ -1078,6 +1078,7 @@ proc rawExecute(c: PCtx, start: int, tos: PStackFrame): TFullReg =
     of opcNKind:
       decodeB(rkInt)
       regs[ra].intVal = ord(regs[rb].node.kind)
+      c.comesFromHeuristic = regs[rb].node.info
     of opcNIntVal:
       decodeB(rkInt)
       let a = regs[rb].node
@@ -1253,8 +1254,16 @@ proc rawExecute(c: PCtx, start: int, tos: PStackFrame): TFullReg =
         internalError(c.debug[pc],
           "request to create a NimNode of invalid kind")
       let cc = regs[rc].node
+
       regs[ra].node = newNodeI(TNodeKind(int(k)),
-        if cc.kind == nkNilLit: c.debug[pc] else: cc.info)
+        if cc.kind != nkNilLit:
+          cc.info
+        elif c.comesFromHeuristic.line > -1:
+          c.comesFromHeuristic
+        elif c.callsite != nil and c.callsite.safeLen > 1:
+          c.callsite[1].info
+        else:
+          c.debug[pc])
       regs[ra].node.flags.incl nfIsRef
     of opcNCopyNimNode:
       decodeB(rkNode)

compiler/vmdef.nim

@@ -188,6 +188,7 @@ type
     features*: TSandboxFlags
     traceActive*: bool
     loopIterations*: int
+    comesFromHeuristic*: TLineInfo # Heuristic for better macro stack traces
 
   TPosition* = distinct int
 
@@ -196,7 +197,8 @@ type
 proc newCtx*(module: PSym): PCtx =
   PCtx(code: @[], debug: @[],
     globals: newNode(nkStmtListExpr), constants: newNode(nkStmtList), types: @[],
-    prc: PProc(blocks: @[]), module: module, loopIterations: MaxLoopIterations)
+    prc: PProc(blocks: @[]), module: module, loopIterations: MaxLoopIterations,
+    comesFromHeuristic: unknownLineInfo())
 
 proc refresh*(c: PCtx, module: PSym) =
   c.module = module