fixes #1323

compiler/vmgen.nim

@@ -1244,12 +1244,15 @@ proc genRdVar(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags) =
       # see tests/t99bott for an example that triggers it:
       cannotEval(n)
 
+template needsRegLoad(): expr =
+  gfAddrOf notin flags and fitsRegister(n.typ.skipTypes({tyVar}))
+
 proc genArrAccess2(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode;
                    flags: TGenFlags) =
   let a = c.genx(n.sons[0], flags)
   let b = c.genIndex(n.sons[1], n.sons[0].typ)
   if dest < 0: dest = c.getTemp(n.typ)
-  if gfAddrOf notin flags and fitsRegister(n.typ):
+  if needsRegLoad():
     var cc = c.getTemp(n.typ)
     c.gABC(n, opc, cc, a, b)
     c.gABC(n, opcNodeToReg, dest, cc)
@@ -1265,7 +1268,7 @@ proc genObjAccess(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags) =
   let a = c.genx(n.sons[0], flags)
   let b = genField(n.sons[1])
   if dest < 0: dest = c.getTemp(n.typ)
-  if gfAddrOf notin flags and fitsRegister(n.typ.skipTypes({tyVar})):
+  if needsRegLoad():
     var cc = c.getTemp(n.typ)
     c.gABC(n, opcLdObj, cc, a, b)
     c.gABC(n, opcNodeToReg, dest, cc)
@@ -1700,7 +1703,7 @@ proc genProc(c: PCtx; s: PSym): int =
     c.gABC(body, opcEof, eofInstr.regA)
     c.optimizeJumps(result)
     s.offset = c.prc.maxSlots
-    #if s.name.s == "get_data":
+    #if s.name.s == "calc":
     #  echo renderTree(body)
     #  c.echoCode(result)
     c.prc = oldPrc

tests/macros/tbugs.nim

@@ -11,7 +11,8 @@ true
 true
 nil'''
 
-output: '''test'''
+output: '''test
+2'''
 """
 
 type
@@ -78,3 +79,12 @@ macro testnilcheck(): stmt =
   discard nilcheck()
 
 testnilcheck()
+
+# bug #1323
+
+proc calc(): array[1, int] =
+  result[0].inc()
+  result[0].inc()
+
+const c = calc()
+echo c[0]

todo.txt

@@ -7,13 +7,13 @@ version 0.9.6
 Concurrency
 -----------
 
+- 'gcsafe' inferrence needs to be fixed
 - the disjoint checker needs to deal with 'a = spawn f(); g = spawn f()'
 - implement 'deepCopy' builtin
 - implement 'foo[1..4] = spawn(f[4..7])'
 - support for exception propagation
 - Minor: The copying of the 'ref Promise' into the thead local storage only
   happens to work due to the write barrier's implementation
-- 'gcsafe' inferrence needs to be fixed
 - implement lock levels --> first without the more complex race avoidance
 - document the new 'spawn' and 'parallel' statements