Throw error when cannot resolve first argument's type in type_structure

Summary:
The following fatals in HHVM and is not caught by Hack.

```
<?hh

type MyCoolType = shape(
  'a' => int,
  ...
);

<<__EntryPoint>>
function main(): void {
    PHP\var_dump(type_structure(MyCoolType::class, 'TUhOh'));
}
```

This diff makes Hack throw an error when we can't properly resolve the type of the first argument to `type_structure`. Previously, we were typing the result of this to be `Tany` and not reporting an error.

We should not allow type alias's here at all in part because we cannot support the type alias resolution at HackC time and HHVM does not support resolving type aliases here.

Reviewed By: Wilfred

Differential Revision: D39483470

fbshipit-source-id: 7bced5c09f5ac0210c752774a566a70d365dce42

Author: Thomas Jiang

hphp/hack/src/errors/typing_error.ml

@@ -2058,7 +2058,10 @@ module Primary = struct
       }
     | Assign_during_case of Pos.t
     | Invalid_classname of Pos.t
-    | Illegal_type_structure of Pos.t
+    | Illegal_type_structure of {
+        pos: Pos.t;
+        msg: string;
+      }
     | Illegal_typeconst_direct_access of Pos.t
     | Wrong_expression_kind_attribute of {
         pos: Pos.t;
@@ -3860,17 +3863,15 @@ module Primary = struct
       lazy [],
       [] )
 
-  let illegal_type_structure pos =
+  let illegal_type_structure pos msg =
     let claim =
       lazy
-        (let errmsg = "second argument is not a string" in
-         let msg =
+        (let msg =
            "The two arguments to `type_structure()` must be:"
            ^ "\n - first: `ValidClassname::class` or an object of that class"
            ^ "\n - second: a single-quoted string literal containing the name"
-           ^ " of a type constant of that class"
-           ^ "\n"
-           ^ errmsg
+           ^ " of a type constant of that class\n"
+           ^ msg
          in
          (pos, msg))
     in
@@ -5796,7 +5797,7 @@ module Primary = struct
       local_variable_modified_twice pos pos_modifieds
     | Assign_during_case pos -> assign_during_case pos
     | Invalid_classname pos -> invalid_classname pos
-    | Illegal_type_structure pos -> illegal_type_structure pos
+    | Illegal_type_structure { pos; msg } -> illegal_type_structure pos msg
     | Illegal_typeconst_direct_access pos -> illegal_typeconst_direct_access pos
     | Wrong_expression_kind_attribute
         {

hphp/hack/src/errors/typing_error.mli

@@ -803,7 +803,10 @@ module Primary : sig
       }
     | Assign_during_case of Pos.t
     | Invalid_classname of Pos.t
-    | Illegal_type_structure of Pos.t
+    | Illegal_type_structure of {
+        pos: Pos.t;
+        msg: string;
+      }
     | Illegal_typeconst_direct_access of Pos.t
     | Wrong_expression_kind_attribute of {
         pos: Pos.t;

hphp/hack/src/typing/typing.ml

@@ -6956,10 +6956,23 @@ and dispatch_call
                 ((), p1, CIexpr e1_)
             in
             let result = class_const ~incl_tc:true env p (cid, (p, cst)) in
+            let () =
+              match result with
+              | (_, (ty, _, _), _) when Typing_utils.is_any env ty ->
+                Errors.add_typing_error
+                  Typing_error.(
+                    primary
+                    @@ Primary.Illegal_type_structure
+                         { pos; msg = "Could not resolve the type constant" })
+              | _ -> ()
+            in
             (result, should_forget_fakes)
           | _ ->
             Errors.add_typing_error
-              Typing_error.(primary @@ Primary.Illegal_type_structure pos);
+              Typing_error.(
+                primary
+                @@ Primary.Illegal_type_structure
+                     { pos; msg = "Second argument is not a string" });
             let result = expr_error env (Reason.Rwitness pos) e in
             (result, should_forget_fakes))
         | _ -> assert false)

hphp/hack/test/typecheck/inout/pseudofunction_with_signature.php.exp

@@ -2,6 +2,11 @@ File "pseudofunction_with_signature.php", line 8, characters 15-22:
 Unexpected `inout` annotation for argument (Typing[4183])
   File "Shapes.hhi", line 40, characters 17-22:
   This is a normal parameter (does not have `inout`)
+File "pseudofunction_with_signature.php", line 9, characters 3-16:
+The two arguments to `type_structure()` must be:
+ - first: `ValidClassname::class` or an object of that class
+ - second: a single-quoted string literal containing the name of a type constant of that class
+Could not resolve the type constant (Typing[4150])
 File "pseudofunction_with_signature.php", line 9, characters 28-30:
 No class constant `T` in `dict` (Typing[4090])
   File "hackarray.hhi", line 29, characters 22-25:

hphp/hack/test/typecheck/type_structure/type_structure4.php.exp

@@ -1,2 +1,7 @@
 File "type_structure4.php", line 4, characters 18-33:
 Unbound name: `NonExistentClass` (an object type) (Naming[2049])
+File "type_structure4.php", line 4, characters 3-16:
+The two arguments to `type_structure()` must be:
+ - first: `ValidClassname::class` or an object of that class
+ - second: a single-quoted string literal containing the name of a type constant of that class
+Could not resolve the type constant (Typing[4150])

hphp/hack/test/typecheck/type_structure/type_structure5.php.exp

@@ -2,4 +2,4 @@ File "type_structure5.php", line 6, characters 3-16:
 The two arguments to `type_structure()` must be:
  - first: `ValidClassname::class` or an object of that class
  - second: a single-quoted string literal containing the name of a type constant of that class
-second argument is not a string (Typing[4150])
+Second argument is not a string (Typing[4150])

hphp/hack/test/typecheck/type_structure/type_structure6.php.exp

@@ -1,4 +1,9 @@
+File "type_structure6.php", line 6, characters 3-16:
+The two arguments to `type_structure()` must be:
+ - first: `ValidClassname::class` or an object of that class
+ - second: a single-quoted string literal containing the name of a type constant of that class
+Could not resolve the type constant (Typing[4150])
 File "type_structure6.php", line 6, characters 28-30:
 No class constant `T` in `C` (Typing[4090])
-File "type_structure6.php", line 3, characters 7-7:
-Declaration of `C` is here
+  File "type_structure6.php", line 3, characters 7-7:
+  Declaration of `C` is here

hphp/hack/test/typecheck/type_structure/type_structure8.php.exp

@@ -1,2 +1,7 @@
+File "type_structure8.php", line 8, characters 3-16:
+The two arguments to `type_structure()` must be:
+ - first: `ValidClassname::class` or an object of that class
+ - second: a single-quoted string literal containing the name of a type constant of that class
+Could not resolve the type constant (Typing[4150])
 File "type_structure8.php", line 8, characters 18-20:
 Was expecting a class, but got a string (Typing[4026])

hphp/hack/test/typecheck/type_structure_typename.php

@@ -0,0 +1,7 @@
+<?hh
+
+type MyTypename = int;
+
+function test(): void {
+  type_structure(MyTypename::class, 'Nonsense');
+}

hphp/hack/test/typecheck/type_structure_typename.php.exp

@@ -0,0 +1,5 @@
+File "type_structure_typename.php", line 6, characters 3-16:
+The two arguments to `type_structure()` must be:
+ - first: `ValidClassname::class` or an object of that class
+ - second: a single-quoted string literal containing the name of a type constant of that class
+Could not resolve the type constant (Typing[4150])