fix nim-lang#12559 Referring to a static nil param is impossible

bung87 · Nov 6, 2022 · 5541d25 · 5541d25
1 parent fc8bfd7
commit 5541d25
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diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
@@ -1387,6 +1387,8 @@ proc builtinFieldAccess(c: PContext; n: PNode; flags: var TExprFlags): PNode =
     return
 
   n[0] = semExprWithType(c, n[0], flags+{efDetermineType, efWantIterable})
+  if n[0].kind == nkNilLit:
+    localError(c.config, n.info, "nil literal access")
   #restoreOldStyleType(n[0])
   var i = considerQuotedIdent(c, n[1], n)
   var ty = n[0].typ

diff --git a/compiler/sigmatch.nim b/compiler/sigmatch.nim
@@ -2118,6 +2118,9 @@ proc paramTypesMatchAux(m: var TCandidate, f, a: PType,
     inc(m.subtypeMatches)
     if f.kind == tyTypeDesc:
       result = arg
+    elif f.skipTypes({tyStatic}).kind in {tyRef,tyPtr} and 
+        arg.typ.skipTypes({tyStatic}).kind == tyNil:
+      result = arg
     else:
       result = implicitConv(nkHiddenSubConv, f, arg, m, c)
   of isSubrange:

diff --git a/tests/statictypes/t12559.nim b/tests/statictypes/t12559.nim
@@ -0,0 +1,13 @@
+discard """
+  errormsg: '''nil literal access'''
+  line: 11
+"""
+
+
+
+type T = ref object
+  x: int
+
+proc f(arg:static  T) = discard arg.x
+
+f nil