Add regression test for #8942 (#3321)

Author: chrchr-github

test/testconstructors.cpp

@@ -79,6 +79,7 @@ class TestConstructors : public TestFixture {
         TEST_CASE(simple12); // ticket #4620
         TEST_CASE(simple13); // #5498 - no constructor, c++11 assignments
         TEST_CASE(simple14); // #6253 template base
+        TEST_CASE(simple15); // #8942 multiple arguments, decltype
 
         TEST_CASE(noConstructor1);
         TEST_CASE(noConstructor2);
@@ -486,6 +487,23 @@ class TestConstructors : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
+    void simple15() { // #8942
+      check("class A\n"
+            "{\n"
+            "public:\n"
+            "  int member;\n"
+            "};\n"
+            "class B\n"
+            "{\n"
+            "public:\n"
+            "  B(const decltype(A::member)& x, const decltype(A::member)& y) : x(x), y(y) {}\n"
+            "private:\n"
+            "  const decltype(A::member)& x;\n"
+            "  const decltype(A::member)& y;\n"
+            "};\n");
+      ASSERT_EQUALS("", errout.str());
+    }
+
     void noConstructor1() {
         // There are nonstatic member variables - constructor is needed
         check("class Fred\n"