fixes #942

compiler/semstmts.nim

@@ -1320,7 +1320,7 @@ proc semStmtList(c: PContext, n: PNode, flags: TExprFlags): PNode =
       if n.sons[i].typ == enforceVoidContext or usesResult(n.sons[i]):
         voidContext = true
         n.typ = enforceVoidContext
-      if i == last and efWantValue in flags:
+      if i == last and (length == 1 or efWantValue in flags):
         n.typ = n.sons[i].typ
         if not isEmptyType(n.typ): n.kind = nkStmtListExpr
       elif i != last or voidContext or c.inTypeClass > 0:

tests/discard/tdiscardable.nim

@@ -11,3 +11,19 @@ proc q[T](x, y: T): T {.discardable.} =
 p(8, 2)
 q[float](0.8, 0.2)
 
+# bug #942
+
+template maybeMod(x: Tinteger, module:Natural):expr =
+  if module > 0: x mod module
+  else: x
+
+proc foo(b: int):int =
+  var x = 1
+  result = x.maybeMod(b) # Works fine
+
+proc bar(b: int):int =
+  result = 1
+  result = result.maybeMod(b) # Error: value returned by statement has to be discarded
+
+echo foo(0)
+echo bar(0)

tests/exprs/texprstmt.nim

@@ -1,6 +1,6 @@
 discard """
   line: 10
-  errormsg: "value returned by statement has to be discarded"
+  errormsg: "value of type 'string' has to be discarded"
 """
 
 # bug #578