diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
index c0ed2bcc0..aa5d496d1 100644
--- a/src/hb-ot-layout-gsubgpos.hh
+++ b/src/hb-ot-layout-gsubgpos.hh
@@ -1642,9 +1642,8 @@ struct Rule
 	       const hb_map_t *klass_map = nullptr) const
   {
     TRACE_SUBSET (this);
-
-    const hb_array_t<const HBUINT16> input = inputZ.as_array ((inputCount ? inputCount - 1 : 0));
-    if (!input.length) return_trace (false);
+    if (unlikely (!inputCount)) return_trace (false);
+    const hb_array_t<const HBUINT16> input = inputZ.as_array (inputCount - 1);
 
     const hb_map_t *mapping = klass_map == nullptr ? c->plan->glyph_map : klass_map;
     if (!hb_all (input, mapping)) return_trace (false);
diff --git a/test/subset/data/Makefile.am b/test/subset/data/Makefile.am
index a69005ab9..4934fa66a 100644
--- a/test/subset/data/Makefile.am
+++ b/test/subset/data/Makefile.am
@@ -33,6 +33,7 @@ EXTRA_DIST += \
 	expected/layout.gdef \
 	expected/layout.gdef.glyphset \
 	expected/layout.context \
+	expected/layout.context_format2 \
 	expected/layout.gdef-varstore \
 	expected/layout.gdef-attachlist \
 	expected/layout.notonastaliqurdu \
diff --git a/test/subset/data/Makefile.sources b/test/subset/data/Makefile.sources
index c1a70ba90..c9597e0e2 100644
--- a/test/subset/data/Makefile.sources
+++ b/test/subset/data/Makefile.sources
@@ -13,6 +13,7 @@ TESTS = \
 	tests/glyf_bug_3131.tests \
 	tests/japanese.tests \
 	tests/layout.context.tests \
+	tests/layout.context_format2.tests \
 	tests/layout.gdef-attachlist.tests \
 	tests/layout.gdef-varstore.tests \
 	tests/layout.gdef.tests \
diff --git a/test/subset/data/expected/layout.context_format2/NotoSansNewa-Regular.layout-test-retain-gids.retain-all-codepoint.ttf b/test/subset/data/expected/layout.context_format2/NotoSansNewa-Regular.layout-test-retain-gids.retain-all-codepoint.ttf
new file mode 100644
index 000000000..c2ef8fed6
Binary files /dev/null and b/test/subset/data/expected/layout.context_format2/NotoSansNewa-Regular.layout-test-retain-gids.retain-all-codepoint.ttf differ
diff --git a/test/subset/data/expected/layout.context_format2/NotoSansNewa-Regular.layout-test.retain-all-codepoint.ttf b/test/subset/data/expected/layout.context_format2/NotoSansNewa-Regular.layout-test.retain-all-codepoint.ttf
new file mode 100644
index 000000000..c2ef8fed6
Binary files /dev/null and b/test/subset/data/expected/layout.context_format2/NotoSansNewa-Regular.layout-test.retain-all-codepoint.ttf differ
diff --git a/test/subset/data/fonts/NotoSansNewa-Regular.ttf b/test/subset/data/fonts/NotoSansNewa-Regular.ttf
new file mode 100644
index 000000000..b79b9cb00
Binary files /dev/null and b/test/subset/data/fonts/NotoSansNewa-Regular.ttf differ
diff --git a/test/subset/data/tests/layout.context_format2.tests b/test/subset/data/tests/layout.context_format2.tests
new file mode 100644
index 000000000..019fb94dc
--- /dev/null
+++ b/test/subset/data/tests/layout.context_format2.tests
@@ -0,0 +1,9 @@
+FONTS:
+NotoSansNewa-Regular.ttf
+
+PROFILES:
+layout-test.txt
+layout-test-retain-gids.txt
+
+SUBSETS:
+*
diff --git a/test/subset/meson.build b/test/subset/meson.build
index 729aa3bfc..a1aa7f12e 100644
--- a/test/subset/meson.build
+++ b/test/subset/meson.build
@@ -25,6 +25,7 @@ tests = [
   'layout.gdef.glyphset',
   'layout.khmer',
   'layout.context',
+  'layout.context_format2',
   'layout.gdef-varstore',
   'layout.gdef-attachlist',
   'layout.notonastaliqurdu',