Fix typecheck crashes

We didn't fill in the m_namedEntity field for hiphop-only type
hints in non-hiphop mode, resulting in crashes when we tried to
use them.

Regardless of mode, we didn't check self or parent before
checking a non-object parameter, resulting in asserts in
dbg builds and seg-faults int opt builds.

hphp/runtime/vm/type_constraint.cpp

@@ -72,7 +72,9 @@ void TypeConstraint::init() {
   Type dtype;
   TRACE(5, "TypeConstraint: this %p type %s, nullable %d\n",
         this, typeName->data(), nullable());
-  if (!mapGet(s_typeNamesToTypes, typeName, &dtype)) {
+  if (!mapGet(s_typeNamesToTypes, typeName, &dtype) ||
+      !(hhType() || dtype.m_dt == KindOfArray || dtype.isParent() ||
+        dtype.isSelf())) {
     TRACE(5, "TypeConstraint: this %p no such type %s, treating as object\n",
           this, typeName->data());
     m_type = { KindOfObject, Precise };
@@ -80,15 +82,11 @@ void TypeConstraint::init() {
     TRACE(5, "TypeConstraint: NamedEntity: %p\n", m_namedEntity);
     return;
   }
-  if (hhType() || dtype.m_dt == KindOfArray || dtype.isParent() ||
-      dtype.isSelf()) {
-    m_type = dtype;
-  } else {
-    m_type = { KindOfObject, Precise };
-  }
+  m_type = dtype;
   assert(m_type.m_dt != KindOfStaticString);
   assert(IMPLIES(isParent(), m_type.m_dt == KindOfObject));
   assert(IMPLIES(isSelf(), m_type.m_dt == KindOfObject));
+  assert(IMPLIES(isCallable(), m_type.m_dt == KindOfObject));
 }
 
 /*
@@ -186,7 +184,7 @@ TypeConstraint::check(const TypedValue* tv, const Func* func) const {
     if (isCallable()) {
       return f_is_callable(tvAsCVarRef(tv));
     }
-    return checkTypedefNonObj(tv);
+    return isPrecise() && checkTypedefNonObj(tv);
   }
 
   return equivDataTypes(m_type.m_dt, tv->m_type);

hphp/runtime/vm/type_constraint.h

@@ -56,6 +56,9 @@ protected:
     constexpr bool isCallable() const {
       return m_metatype == Callable;
     }
+    constexpr bool isPrecise() const {
+      return m_metatype == Precise;
+    }
   };
 
   // m_type represents the DataType to check on.  We don't know
@@ -109,6 +112,10 @@ public:
     return m_type.isCallable();
   }
 
+  bool isPrecise() const {
+    return m_type.isPrecise();
+  }
+
   bool isObjectOrTypedef() const {
     assert(IMPLIES(isParent(), m_type.m_dt == KindOfObject));
     assert(IMPLIES(isSelf(), m_type.m_dt == KindOfObject));

hphp/test/quick/fail_self.php

@@ -0,0 +1,7 @@
+<?php
+class X {
+  function test(self $s) {
+    var_dump($s);
+  }
+}
+X::test("hello");

hphp/test/quick/fail_self.php.expectf

@@ -0,0 +1 @@
+HipHop Fatal error: Argument 1 passed to X::test() must be an instance of X, string given in %s/test/quick/fail_self.php on line 5