From 74189a07c56eb9b1b8e74e727b523561e499c125 Mon Sep 17 00:00:00 2001
From: Marshall Roch <mroch@fb.com>
Date: Tue, 31 Oct 2017 12:52:09 -0700
Subject: [PATCH] [parser] forbid reserved types in `opaque type`

Summary: `opaque type string = number` would overwrite the `string` builtin. reserved types should be disallowed.

Reviewed By: samwgoldman

Differential Revision: D6199767

fbshipit-source-id: f0f5bdf44d8cff0d444381747f0ebb5a94df3ffa
---
 src/parser/statement_parser.ml                |  2 +-
 .../opaque_aliases/invalid/reserved_type.js   |  1 +
 .../invalid/reserved_type.tree.json           | 34 +++++++++++++++++++
 .../opaque_aliases/valid/reserved_value.js    |  1 +
 .../valid/reserved_value.tree.json            | 28 +++++++++++++++
 5 files changed, 65 insertions(+), 1 deletion(-)
 create mode 100644 src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.js
 create mode 100644 src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.tree.json
 create mode 100644 src/parser/test/flow/types/opaque_aliases/valid/reserved_value.js
 create mode 100644 src/parser/test/flow/types/opaque_aliases/valid/reserved_value.tree.json

diff --git a/src/parser/statement_parser.ml b/src/parser/statement_parser.ml
index c61ae2994d0..2f913fbbf77 100644
--- a/src/parser/statement_parser.ml
+++ b/src/parser/statement_parser.ml
@@ -558,7 +558,7 @@ module Statement
     Expect.token env T_OPAQUE;
     Expect.token env T_TYPE;
     Eat.push_lex_mode env Lex_mode.TYPE;
-    let id = Parse.identifier env in
+    let id = Type.type_identifier env in
     let typeParameters = Type.type_parameter_declaration_with_defaults env in
     let supertype = match Peek.token env with
     | T_COLON ->
diff --git a/src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.js b/src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.js
new file mode 100644
index 00000000000..af9115c3219
--- /dev/null
+++ b/src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.js
@@ -0,0 +1 @@
+opaque type string = number;
diff --git a/src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.tree.json b/src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.tree.json
new file mode 100644
index 00000000000..6d21a6fe256
--- /dev/null
+++ b/src/parser/test/flow/types/opaque_aliases/invalid/reserved_type.tree.json
@@ -0,0 +1,34 @@
+{
+  "errors":[
+    {
+      "loc":{"source":null,"start":{"line":1,"column":12},"end":{"line":1,"column":18}},
+      "message":"Unexpected reserved type"
+    }
+  ],
+  "type":"Program",
+  "loc":{"source":null,"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+  "range":[0,28],
+  "body":[
+    {
+      "type":"OpaqueType",
+      "loc":{"source":null,"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+      "range":[0,28],
+      "id":{
+        "type":"Identifier",
+        "loc":{"source":null,"start":{"line":1,"column":12},"end":{"line":1,"column":18}},
+        "range":[12,18],
+        "name":"string",
+        "typeAnnotation":null,
+        "optional":false
+      },
+      "typeParameters":null,
+      "impltype":{
+        "type":"NumberTypeAnnotation",
+        "loc":{"source":null,"start":{"line":1,"column":21},"end":{"line":1,"column":27}},
+        "range":[21,27]
+      },
+      "supertype":null
+    }
+  ],
+  "comments":[]
+}
diff --git a/src/parser/test/flow/types/opaque_aliases/valid/reserved_value.js b/src/parser/test/flow/types/opaque_aliases/valid/reserved_value.js
new file mode 100644
index 00000000000..ee2234d431b
--- /dev/null
+++ b/src/parser/test/flow/types/opaque_aliases/valid/reserved_value.js
@@ -0,0 +1 @@
+opaque type switch = number;
diff --git a/src/parser/test/flow/types/opaque_aliases/valid/reserved_value.tree.json b/src/parser/test/flow/types/opaque_aliases/valid/reserved_value.tree.json
new file mode 100644
index 00000000000..48a55cc1a83
--- /dev/null
+++ b/src/parser/test/flow/types/opaque_aliases/valid/reserved_value.tree.json
@@ -0,0 +1,28 @@
+{
+  "type":"Program",
+  "loc":{"source":null,"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+  "range":[0,28],
+  "body":[
+    {
+      "type":"OpaqueType",
+      "loc":{"source":null,"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+      "range":[0,28],
+      "id":{
+        "type":"Identifier",
+        "loc":{"source":null,"start":{"line":1,"column":12},"end":{"line":1,"column":18}},
+        "range":[12,18],
+        "name":"switch",
+        "typeAnnotation":null,
+        "optional":false
+      },
+      "typeParameters":null,
+      "impltype":{
+        "type":"NumberTypeAnnotation",
+        "loc":{"source":null,"start":{"line":1,"column":21},"end":{"line":1,"column":27}},
+        "range":[21,27]
+      },
+      "supertype":null
+    }
+  ],
+  "comments":[]
+}