cmd/compile: fix delay transformation in *subster.node()

Add OCALL, OCALLFUNC, OCALLMETH, OCALLINTER, ODYNAMICDOTTYPE transformations to the CALL check switch statement.

Fixes #48042

Change-Id: Ied93efd979c5b2c56b72fad26fccfd9f887361d3
Reviewed-on: https://go-review.googlesource.com/c/go/+/345949
Trust: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>
Reviewed-by: Dan Scales <danscales@google.com>

src/cmd/compile/internal/noder/stencil.go

@@ -1095,6 +1095,9 @@ func (subst *subster) node(n ir.Node) ir.Node {
 				// or channel receive to compute function value.
 				transformCall(call)
 
+			case ir.OCALL, ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER, ir.ODYNAMICDOTTYPE:
+				transformCall(call)
+
 			case ir.OFUNCINST:
 				// A call with an OFUNCINST will get transformed
 				// in stencil() once we have created & attached the

test/typeparam/issue48042.go

@@ -0,0 +1,77 @@
+// 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
+
+import (
+	"fmt"
+	"reflect"
+)
+
+type G[T any] interface {
+	g() func()(*T)
+}
+type Foo[T any] struct {
+
+}
+// OCALL
+func (l *Foo[T]) f1() (*T) {
+	return g[T]()()
+}
+// OCALLFUNC
+func (l *Foo[T]) f2() (*T) {
+	var f = g[T]
+	return f()()
+}
+// OCALLMETH
+func (l *Foo[T]) f3() (*T) {
+	return l.g()()
+}
+// OCALLINTER
+func (l *Foo[T]) f4() (*T) {
+	var g G[T] = l
+	return g.g()()
+}
+// ODYNAMICDOTTYPE
+func (l *Foo[T]) f5() (*T) {
+	var x interface{}
+	x = g[T]
+	return x.(func()func()(*T))()()
+}
+func (l *Foo[T]) g() func() (*T) {
+	return func() (*T) {
+		t := new(T)
+		reflect.ValueOf(t).Elem().SetInt(100)
+		return t
+	}
+}
+func g[T any]() func() (*T) {
+	return func() (*T) {
+		t := new(T)
+		reflect.ValueOf(t).Elem().SetInt(100)
+		return t
+	}
+}
+
+func main() {
+	foo := Foo[int]{}
+	// Make sure the function conversion is correct
+	if n := *(foo.f1()) ; n != 100{
+		panic(fmt.Sprintf("%v",n))
+	}
+	if n := *(foo.f2()) ; n != 100{
+		panic(fmt.Sprintf("%v",n))
+	}
+	if n := *(foo.f3()) ; n != 100{
+		panic(fmt.Sprintf("%v",n))
+	}
+	if n := *(foo.f4()) ; n != 100{
+		panic(fmt.Sprintf("%v",n))
+	}
+	if n := *(foo.f5()) ; n != 100{
+		panic(fmt.Sprintf("%v",n))
+	}
+}