fix nim-lang#8011

krux02 · Nov 8, 2018 · 3cbb8e8 · 3cbb8e8
1 parent a0e89bd
commit 3cbb8e8
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/compiler/ccgtypes.nim b/compiler/ccgtypes.nim
@@ -146,6 +146,8 @@ proc mapType(conf: ConfigRef; typ: PType): TCTypeKind =
     return mapType(conf, typ.lastSon)
   of tyGenericBody, tyGenericInst, tyGenericParam, tyDistinct, tyOrdinal,
      tyTypeDesc, tyAlias, tySink, tyInferred:
+    if typ.sons.len == 0:
+      internalError(conf, "typ has no last son")
     result = mapType(conf, lastSon(typ))
   of tyEnum:
     if firstOrd(conf, typ) < 0:

diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
@@ -41,8 +41,12 @@ proc semDiscard(c: PContext, n: PNode): PNode =
   checkSonsLen(n, 1, c.config)
   if n.sons[0].kind != nkEmpty:
     n.sons[0] = semExprWithType(c, n.sons[0])
-    if isEmptyType(n.sons[0].typ) or n.sons[0].typ.kind == tyNone or n.sons[0].kind == nkTypeOfExpr:
+    let sonType = n.sons[0].typ
+    if isEmptyType(sonType) or sonType.kind == tyNone or n.sons[0].kind == nkTypeOfExpr:
       localError(c.config, n.info, errInvalidDiscard)
+    if sonType.kind == tyProc:
+      # tyProc is disallowed to prevent ``discard foo`` to pass, when ``discard foo()`` is meant.
+      localError(c.config, n.info, "illegal discard proc, did you mean: " & $n[0] & "()")
 
 proc semBreakOrContinue(c: PContext, n: PNode): PNode =
   result = n