test: add test case for wasmexport parameter types

For #65199.

Change-Id: Iecd11281706201a655b51583a08318b5ffd8ab04
Reviewed-on: https://go-review.googlesource.com/c/go/+/604975
Reviewed-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

test/wasmexport2.go

@@ -0,0 +1,58 @@
+// errorcheck
+
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Verify that wasmexport supports allowed types and rejects
+// unallowed types.
+
+//go:build wasm
+
+package p
+
+import "unsafe"
+
+//go:wasmexport good1
+func good1(int32, uint32, int64, uint64, float32, float64, unsafe.Pointer) {} // allowed types
+
+type MyInt32 int32
+
+//go:wasmexport good2
+func good2(MyInt32) {} // named type is ok
+
+//go:wasmexport good3
+func good3() int32 { return 0 } // one result is ok
+
+//go:wasmexport bad1
+func bad1(string) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+//go:wasmexport bad2
+func bad2(any) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+//go:wasmexport bad3
+func bad3(func()) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+//go:wasmexport bad4
+func bad4(uint8) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+// Pointer types are not allowed, except unsafe.Pointer.
+// Struct and array types are also not allowed.
+// If proposal 66984 is accepted and implemented, we may allow them.
+
+//go:wasmexport bad5
+func bad5(*int32) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+type S struct { x, y int32 }
+
+//go:wasmexport bad6
+func bad6(S) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+//go:wasmexport bad7
+func bad7(*S) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+//go:wasmexport bad8
+func bad8([4]int32) {} // ERROR "go:wasmexport: unsupported parameter type"
+
+//go:wasmexport toomanyresults
+func toomanyresults() (int32, int32) { return 0, 0 } // ERROR "go:wasmexport: too many return values"