From 640ad101fc63a76b72714076cc4bd3eb99a68636 Mon Sep 17 00:00:00 2001
From: Nishanth Shanmugham <nishanth.gerrard@gmail.com>
Date: Fri, 3 Jun 2022 11:40:42 +0530
Subject: [PATCH] add bugs section in readme for type parameter switch
 statements

---
 README.md                      |  6 ++++++
 testdata/xxx/typeparam/main.go | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 testdata/xxx/typeparam/main.go

diff --git a/README.md b/README.md
index b843ee8..3992704 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,12 @@ The package provides an `Analyzer` that follows the guidelines in the
 [`go/analysis`][3] package; this should make it possible to integrate
 exhaustive with your own analysis driver program.
 
+## Bugs
+
+`exhaustive` does not report missing cases if the switch statement
+switches on a type parameterized type. See [this
+issue](https://github.com/nishanths/exhaustive/issues/31) for details.
+
 ## Example
 
 Given the enum
diff --git a/testdata/xxx/typeparam/main.go b/testdata/xxx/typeparam/main.go
new file mode 100644
index 0000000..6efc2da
--- /dev/null
+++ b/testdata/xxx/typeparam/main.go
@@ -0,0 +1,32 @@
+package typeparam
+
+// Testing instructions:
+//  $ go build ./cmd/exhaustive
+//  $ ./exhaustive ./testdata/xxx/typeparam
+
+type M int
+
+const (
+	A M = iota
+	B
+)
+
+type N uint
+
+const (
+	C N = iota
+	D
+)
+
+func foo[T M](v T) {
+	switch v {
+	case T(A):
+	}
+}
+
+func bar[T M | N](v T) {
+	switch v {
+	case T(A):
+	case T(D):
+	}
+}