Fix as-expression irgen for vec/dict

Summary: We didn't bail early for as-expressions when checking for vec/dict in irgen, leading us to emit an is-expression instead of an as-expression.

Reviewed By: oulgen

Differential Revision: D8708371

fbshipit-source-id: e7212873d91f09f7b3783a78a1510dd2a72b42b2

hphp/runtime/vm/jit/irgen-types.cpp

@@ -847,6 +847,7 @@ bool emitIsAsTypeStructWithoutResolvingIfPossible(
       return unionOf(TArr, TVec, TDict, TKeyset);
     case TypeStructure::Kind::T_dict:
     case TypeStructure::Kind::T_vec: {
+      if (asExpr) return false;
       auto const c = popC(env);
       auto const res = kind == TypeStructure::Kind::T_dict
         ? isDictImpl(env, c)

hphp/test/slow/as_expression/dict.php

@@ -0,0 +1,20 @@
+<?hh
+
+function f(mixed $x): void {
+  try {
+    var_dump($x as dict);
+  } catch (TypeAssertionException $_) {
+    echo "not dict: ".gettype($x)."\n";
+  }
+}
+
+f(1);
+f(false);
+f(1.5);
+f('foo');
+f(STDIN);
+f(new stdClass());
+f(vec[]);
+f(dict[]);
+f(keyset[]);
+f(null);

hphp/test/slow/as_expression/dict.php.expect

@@ -0,0 +1,11 @@
+not dict: integer
+not dict: boolean
+not dict: double
+not dict: string
+not dict: resource
+not dict: object
+not dict: vec
+dict(0) {
+}
+not dict: keyset
+not dict: NULL

hphp/test/slow/as_expression/vec.php

@@ -0,0 +1,20 @@
+<?hh
+
+function f(mixed $x): void {
+  try {
+    var_dump($x as vec);
+  } catch (TypeAssertionException $_) {
+    echo "not vec: ".gettype($x)."\n";
+  }
+}
+
+f(1);
+f(false);
+f(1.5);
+f('foo');
+f(STDIN);
+f(new stdClass());
+f(vec[]);
+f(dict[]);
+f(keyset[]);
+f(null);

hphp/test/slow/as_expression/vec.php.expect

@@ -0,0 +1,11 @@
+not vec: integer
+not vec: boolean
+not vec: double
+not vec: string
+not vec: resource
+not vec: object
+vec(0) {
+}
+not vec: dict
+not vec: keyset
+not vec: NULL