4 files changed, 64 insertions, 4 deletions
diff --git a/src/cmd/compile/internal/ir/expr.go b/src/cmd/compile/internal/ir/expr.go
index 65ed3cff66..2d62b22d8c 100644
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@@ -740,6 +740,13 @@ func IsAddressable(n Node) bool {
 	case ODEREF, ODOTPTR:
 		return true
 
+	case OXDOT:
+		// TODO(danscales): remove this case as we remove calls to the old
+		// typechecker in (*irgen).funcBody().
+		if base.Flag.G == 0 {
+			return false
+		}
+		fallthrough
 	case ODOT:
 		n := n.(*SelectorExpr)
 		return IsAddressable(n.X)
diff --git a/src/cmd/compile/internal/noder/expr.go b/src/cmd/compile/internal/noder/expr.go
index 06aa91199c..989ebf236e 100644
--- a/src/cmd/compile/internal/noder/expr.go
+++ b/src/cmd/compile/internal/noder/expr.go
@@ -188,7 +188,7 @@ func (g *irgen) expr0(typ types2.Type, expr syntax.Expr) ir.Node {
 // than in typecheck.go.
 func (g *irgen) selectorExpr(pos src.XPos, typ types2.Type, expr *syntax.SelectorExpr) ir.Node {
 	x := g.expr(expr.X)
-	if x.Type().Kind() == types.TTYPEPARAM {
+	if x.Type().HasTParam() {
 		// Leave a method call on a type param as an OXDOT, since it can
 		// only be fully transformed once it has an instantiated type.
 		n := ir.NewSelectorExpr(pos, ir.OXDOT, x, typecheck.Lookup(expr.Sel.Value))
diff --git a/src/cmd/compile/internal/noder/helpers.go b/src/cmd/compile/internal/noder/helpers.go
index 4cb6bc3eab..2b084ff311 100644
--- a/src/cmd/compile/internal/noder/helpers.go
+++ b/src/cmd/compile/internal/noder/helpers.go
@@ -54,8 +54,11 @@ func Nil(pos src.XPos, typ *types.Type) ir.Node {
 // Expressions
 
 func Addr(pos src.XPos, x ir.Node) *ir.AddrExpr {
-	// TODO(mdempsky): Avoid typecheck.Expr. Probably just need to set OPTRLIT when appropriate.
-	n := typecheck.Expr(typecheck.NodAddrAt(pos, x)).(*ir.AddrExpr)
+	n := typecheck.NodAddrAt(pos, x)
+	switch x.Op() {
+	case ir.OARRAYLIT, ir.OMAPLIT, ir.OSLICELIT, ir.OSTRUCTLIT:
+		n.SetOp(ir.OPTRLIT)
+	}
 	typed(types.NewPtr(x.Type()), n)
 	return n
 }
@@ -125,7 +128,7 @@ func Call(pos src.XPos, typ *types.Type, fun ir.Node, args []ir.Node, dots bool)
 	n.IsDDD = dots
 
 	if fun.Op() == ir.OXDOT {
-		if fun.(*ir.SelectorExpr).X.Type().Kind() != types.TTYPEPARAM {
+		if !fun.(*ir.SelectorExpr).X.Type().HasTParam() {
 			base.FatalfAt(pos, "Expecting type param receiver in %v", fun)
 		}
 		// For methods called in a generic function, don't do any extra
diff --git a/test/typeparam/lockable.go b/test/typeparam/lockable.go
new file mode 100644
index 0000000000..d53817521f
--- /dev/null
+++ b/test/typeparam/lockable.go
@@ -0,0 +1,50 @@
+// 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 "sync"
+
+// A _Lockable is a value that may be safely simultaneously accessed
+// from multiple goroutines via the Get and Set methods.
+type _Lockable[T any] struct {
+	T
+	mu sync.Mutex
+}
+
+// Get returns the value stored in a _Lockable.
+func (l *_Lockable[T]) get() T {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.T
+}
+
+// set sets the value in a _Lockable.
+func (l *_Lockable[T]) set(v T) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.T = v
+}
+
+func main() {
+	sl := _Lockable[string]{T: "a"}
+	if got := sl.get(); got != "a" {
+		panic(got)
+	}
+	sl.set("b")
+	if got := sl.get(); got != "b" {
+		panic(got)
+	}
+
+	il := _Lockable[int]{T: 1}
+	if got := il.get(); got != 1 {
+		panic(got)
+	}
+	il.set(2)
+	if got := il.get(); got != 2 {
+		panic(got)
+	}
+}