Add test for index under lambda

Summary: Doesnt seems to be too useful - with/without can_index constraint it is the same

Differential Revision: D77798584

fbshipit-source-id: 85439582392a2e8e9b01fca1f8f47081a431c382

Author: MarisaKirisame

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index.php

@@ -0,0 +1,5 @@
+<?hh
+function f(): void {
+  $v = vec[0];
+  $f = ($i ==> $v[$i]);
+}

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index.php.exp

@@ -0,0 +1 @@
+No errors

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_int.php

@@ -0,0 +1,6 @@
+<?hh
+function f(): void {
+  $v = vec[0];
+  $f = ($i ==> $v[$i]);
+  $f(0);
+}

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_int.php.exp

@@ -0,0 +1 @@
+No errors

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_int_plus.php

@@ -0,0 +1,6 @@
+<?hh
+function f(): void {
+  $v = vec[0];
+  $f = ($i ==> $v[$i] + $i);
+  $f(0);
+}

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_int_plus.php.exp

@@ -0,0 +1 @@
+No errors

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_plus_int.php

@@ -0,0 +1,6 @@
+<?hh
+function f(): void {
+  $v = vec[0];
+  $f = ($i ==> $v[$i + $i]);
+  $f(0);
+}

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_plus_int.php.exp

@@ -0,0 +1 @@
+No errors

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_string.php

@@ -0,0 +1,6 @@
+<?hh
+function f(): void {
+  $v = vec[0];
+  $f = ($i ==> $v[$i]);
+  $f("a");
+}

hphp/hack/test/typecheck/constraint_array_index/after/lambda_index_string.php.exp

@@ -0,0 +1,6 @@
+ERROR: File "lambda_index_string.php", line 5, characters 6-8:
+Invalid argument (Typing[4110])
+  File "lambda_index_string.php", line 3, characters 8-13:
+  Expected `int` because only `int` can be used to index into a `Vector` or `vec`.
+  File "lambda_index_string.php", line 5, characters 6-8:
+  But got `string`