5 files changed, 59 insertions, 0 deletions
diff --git a/tests/diagnostics/extension-visibility-a.slang b/tests/diagnostics/extension-visibility-a.slang
new file mode 100644
index 000000000..97e4ef85c
--- /dev/null
+++ b/tests/diagnostics/extension-visibility-a.slang
@@ -0,0 +1,17 @@
+// extension-visibility-a.slang
+
+interface IThing
+{
+	int getValue();
+}
+
+// Note: not implementing the interface here!
+struct MyThing
+{
+	int value;
+}
+
+int helper<T : IThing>(T thing)
+{
+	return thing.getValue();
+}
+\ No newline at end of file
diff --git a/tests/diagnostics/extension-visibility-b.slang b/tests/diagnostics/extension-visibility-b.slang
new file mode 100644
index 000000000..7848f2a56
--- /dev/null
+++ b/tests/diagnostics/extension-visibility-b.slang
@@ -0,0 +1,8 @@
+// extension-visibility-b.slang
+
+import extension_visibility_a;
+
+extension MyThing : IThing
+{
+	int getValue() { return value; }	
+}
diff --git a/tests/diagnostics/extension-visibility-c.slang b/tests/diagnostics/extension-visibility-c.slang
new file mode 100644
index 000000000..2d7a5224d
--- /dev/null
+++ b/tests/diagnostics/extension-visibility-c.slang
@@ -0,0 +1,9 @@
+// extension-visibility-c.slang
+
+import extension_visibility_a;
+import extension_visibility_b;
+
+int works(MyThing thing)
+{
+	return helper(thing);
+}
diff --git a/tests/diagnostics/extension-visibility.slang b/tests/diagnostics/extension-visibility.slang
new file mode 100644
index 000000000..029b16b86
--- /dev/null
+++ b/tests/diagnostics/extension-visibility.slang
@@ -0,0 +1,18 @@
+// extension-visibility.slang
+
+// Confirm that visibility of `extensions` is
+// correctly scoped via `import`.
+
+//DIAGNOSTIC_TEST:SIMPLE:
+
+import extension_visibility_a;
+
+// Note: not importing b:
+// import extension_visibility_b;
+
+import extension_visibility_c;
+
+int shouldntWork(MyThing thing)
+{
+	return helper(thing);
+}
diff --git a/tests/diagnostics/extension-visibility.slang.expected b/tests/diagnostics/extension-visibility.slang.expected
new file mode 100644
index 000000000..217dfa188
--- /dev/null
+++ b/tests/diagnostics/extension-visibility.slang.expected
@@ -0,0 +1,7 @@
+result code = -1
+standard error = {
+tests/diagnostics/extension-visibility.slang(17): error 39999: could not specialize generic for arguments of type (MyThing)
+tests/diagnostics/extension-visibility-a.slang(14): note 39999: see declaration of func helper<T>(T) -> int
+}
+standard output = {
+}