From dd1f7cd4f46a61c49c1705799d8a1cea2a0128e0 Mon Sep 17 00:00:00 2001
From: Andrew Kennedy <akenn@fb.com>
Date: Tue, 2 Jan 2018 10:19:47 -0800
Subject: [PATCH] Reuse of classes in use statement

Summary: Fixed a bug in the `combine_names` function that revealed some issues with `use` redefinition errors.

Differential Revision: D6649813

fbshipit-source-id: c43c5a9a783a553e601a9f4c09c701a02576fda3
---
 hphp/hack/src/parser/full_fidelity_parser_errors.ml | 14 +++++++-------
 hphp/test/hackc_failing_tests_slow                  |  1 -
 hphp/test/hackc_repo_failing_tests_slow             |  3 +--
 hphp/test/hhcodegen_failing_tests_slow              |  2 --
 4 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/hphp/hack/src/parser/full_fidelity_parser_errors.ml b/hphp/hack/src/parser/full_fidelity_parser_errors.ml
index f537110ae59..89b228ff1db 100644
--- a/hphp/hack/src/parser/full_fidelity_parser_errors.ml
+++ b/hphp/hack/src/parser/full_fidelity_parser_errors.ml
@@ -70,7 +70,7 @@ let combine_names n1 n2 =
   let len = String.length n1 in
   let has_trailing_slash = String.get n1 (len - 1) = '\\' in
   match has_leading_slash, has_trailing_slash with
-  | true, true -> n1 ^ (String.sub n2 1 (len - 1))
+  | true, true -> n1 ^ (String.sub n2 1 (String.length n2 - 1))
   | false, false -> n1 ^ "\\" ^ n2
   | _ -> n1 ^ n2
 
@@ -1693,7 +1693,8 @@ let require_errors node parents hhvm_compat_mode trait_use_clauses errors =
 
 let check_type_name name namespace_name name_text location names errors =
   begin match SMap.get name_text names.t_classes with
-  | Some { f_location = location; f_is_def = false; _ } ->
+  | Some { f_location = location; f_is_def = false; f_name }
+    when combine_names namespace_name name_text <> f_name ->
     let error =
       make_name_already_used_error name name_text name_text location
         SyntaxError.type_name_is_already_in_use in
@@ -1878,9 +1879,8 @@ let use_class_or_namespace_clause_errors
 
       let map = get_map names in
       match SMap.get short_name map with
-      | Some { f_location = location; f_is_def = is_definition; f_name } ->
-        if qualified_name <> f_name &&
-          (not is_definition
+      | Some { f_location = location; f_is_def = is_definition; _ } ->
+        if (not is_definition
            || (error_on_global_redefinition && is_global_namespace))
         then
           let error =
@@ -1940,8 +1940,8 @@ let use_class_or_namespace_clause_errors
       let names, errors =
         let location = make_location_of_node name in
         match SMap.get short_name names.t_classes with
-        | Some { f_location = loc; f_name; _ } ->
-          if qualified_name = f_name then names, errors
+        | Some { f_location = loc; f_name; f_is_def; _ } ->
+          if qualified_name = f_name && f_is_def then names, errors
           else
           let error =
             make_name_already_used_error name name_text short_name loc
diff --git a/hphp/test/hackc_failing_tests_slow b/hphp/test/hackc_failing_tests_slow
index 9f9cfe8a94b..4ecb30ab528 100644
--- a/hphp/test/hackc_failing_tests_slow
+++ b/hphp/test/hackc_failing_tests_slow
@@ -24,7 +24,6 @@ slow/inout/method-interop-static.php
 slow/inout/side-effects.php
 slow/inout/trait-magic.php
 slow/parser/hh-namespace-conflict-2.php
-slow/parser/hh-namespace-conflict-3.php
 slow/parser/hh-namespace-conflict-6.php
 slow/return_statement/finally-typecheck.php
 slow/using/bad-async.php
diff --git a/hphp/test/hackc_repo_failing_tests_slow b/hphp/test/hackc_repo_failing_tests_slow
index d0b64cc47bb..ea03f053a11 100644
--- a/hphp/test/hackc_repo_failing_tests_slow
+++ b/hphp/test/hackc_repo_failing_tests_slow
@@ -16,7 +16,6 @@ slow/hh_namespace_migration/hh_vector5.php
 slow/inout/bad-call-15.php
 slow/inout/side-effects.php
 slow/parser/hh-namespace-conflict-2.php
-slow/parser/hh-namespace-conflict-3.php
 slow/parser/hh-namespace-conflict-6.php
 slow/return_statement/finally-typecheck.php
 slow/traits/require_constraint_basic_error.php
@@ -25,4 +24,4 @@ slow/using/bad-async.php
 slow/using/bad-function3.php
 slow/using/bad-function4.php
 slow/using/bad-goto1.php
-slow/using/bad-goto2.php
\ No newline at end of file
+slow/using/bad-goto2.php
diff --git a/hphp/test/hhcodegen_failing_tests_slow b/hphp/test/hhcodegen_failing_tests_slow
index d82772b5cf0..96eadcbe11e 100644
--- a/hphp/test/hhcodegen_failing_tests_slow
+++ b/hphp/test/hhcodegen_failing_tests_slow
@@ -3,9 +3,7 @@ slow/hh_namespace_migration/hh_vector5.php
 slow/inout/bad-call-15.php
 slow/inout/side-effects.php
 slow/parser/hh-namespace-conflict-2.php
-slow/parser/hh-namespace-conflict-3.php
 slow/parser/hh-namespace-conflict-6.php
-slow/parser/php-namespace-conflict-3.php
 slow/php7_backported/ns_093.php
 slow/reflection/param_tostring_zendcompat.php
 slow/using/goto.php
\ No newline at end of file
-- 
2.11.4.GIT