cmd/compile: fix CheckSize() calculation for -G=3 and stencils

Because the Align/Width of pointer types are always set when created,
CalcSize() never descends past a pointer. Therefore, we need to do
CheckSize() at every level when creating type. We need to do this for
types creates by types2-to-types1 conversion and also by type
substitution (mostly for stenciling). We also need to do
Defer/ResumeCheckSize() at the top level in each of these cases to deal
with potentially recursive types.

These changes fix issue #47929 and also allow us to remove the
special-case CheckSize() call that causes the problem for issue #47901.

Fixes #47901
Fixes #47929

Change-Id: Icd8192431c145009cd6df2f4ade6db7da0f4dd3e
Reviewed-on: https://go-review.googlesource.com/c/go/+/344829
Trust: Dan Scales <danscales@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

2 files changed, 50 insertions, 0 deletions

diff --git a/test/typeparam/issue47901.go b/test/typeparam/issue47901.go
new file mode 100644
index 0000000000..cd07973011
--- /dev/null
+++ b/test/typeparam/issue47901.go
@@ -0,0 +1,21 @@
+// run -gcflags=-G=3
+
+// Copyright 2021 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.
+
+package main
+
+type Chan[T any] chan Chan[T]
+
+func (ch Chan[T]) recv() Chan[T] {
+	return <-ch
+}
+
+func main() {
+	ch := Chan[int](make(chan Chan[int]))
+	go func() {
+		ch <- make(Chan[int])
+	}()
+	ch.recv()
+}
diff --git a/test/typeparam/issue47929.go b/test/typeparam/issue47929.go
new file mode 100644
index 0000000000..a5636f2c7b
--- /dev/null
+++ b/test/typeparam/issue47929.go
@@ -0,0 +1,29 @@
+// compile -G=3 -p=p
+
+// Copyright 2021 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.
+
+package v4
+
+var sink interface{}
+
+//go:noinline
+func Do(result, body interface{}) {
+	sink = &result
+}
+
+func DataAction(result DataActionResponse, body DataActionRequest) {
+	Do(&result, body)
+}
+
+type DataActionRequest struct {
+	Action *interface{}
+}
+
+type DataActionResponse struct {
+	ValidationErrors *ValidationError
+}
+
+type ValidationError struct {
+}