3 files changed, 25 insertions, 28 deletions

diff --git a/src/cmd/compile/internal/noder/noder.go b/src/cmd/compile/internal/noder/noder.go
index 2b67a91b3f..e1b485b2b3 100644
--- a/src/cmd/compile/internal/noder/noder.go
+++ b/src/cmd/compile/internal/noder/noder.go
@@ -35,7 +35,7 @@ func LoadPackage(filenames []string) {
 	supportsGenerics := base.Flag.G != 0 || buildcfg.Experiment.Unified
 
 	mode := syntax.CheckBranches
-	if supportsGenerics && types.AllowsGoVersion(types.LocalPkg, 1, 18) {
+	if supportsGenerics {
 		mode |= syntax.AllowGenerics
 	}
 
diff --git a/src/cmd/compile/internal/noder/stencil.go b/src/cmd/compile/internal/noder/stencil.go
index 602e88c102..b3ff4b8855 100644
--- a/src/cmd/compile/internal/noder/stencil.go
+++ b/src/cmd/compile/internal/noder/stencil.go
@@ -732,21 +732,15 @@ func (g *irgen) genericSubst(newsym *types.Sym, nameNode *ir.Name, shapes []*typ
 	g.instTypeList = append(g.instTypeList, subst.ts.InstTypeList...)
 
 	if doubleCheck {
-		okConvs := map[ir.Node]bool{}
 		ir.Visit(newf, func(n ir.Node) {
-			if n.Op() == ir.OIDATA {
-				// IDATA(OCONVIFACE(x)) is ok, as we don't use the type of x.
-				// TODO: use some other op besides OCONVIFACE. ONEW might work
-				// (with appropriate direct vs. indirect interface cases).
-				okConvs[n.(*ir.UnaryExpr).X] = true
+			if n.Op() != ir.OCONVIFACE {
+				return
 			}
-			if n.Op() == ir.OCONVIFACE && !okConvs[n] {
-				c := n.(*ir.ConvExpr)
-				if c.X.Type().HasShape() {
-					ir.Dump("BAD FUNCTION", newf)
-					ir.Dump("BAD CONVERSION", c)
-					base.Fatalf("converting shape type to interface")
-				}
+			c := n.(*ir.ConvExpr)
+			if c.X.Type().HasShape() {
+				ir.Dump("BAD FUNCTION", newf)
+				ir.Dump("BAD CONVERSION", c)
+				base.Fatalf("converting shape type to interface")
 			}
 		})
 	}
@@ -1054,6 +1048,13 @@ func (subst *subster) node(n ir.Node) ir.Node {
 			case ir.OCLOSURE:
 				transformCall(call)
 
+			case ir.ODEREF, ir.OINDEX, ir.OINDEXMAP, ir.ORECV:
+				// Transform a call that was delayed because of the
+				// use of typeparam inside an expression that required
+				// a pointer dereference, array indexing, map indexing,
+				// or channel receive to compute function value.
+				transformCall(call)
+
 			case ir.OFUNCINST:
 				// A call with an OFUNCINST will get transformed
 				// in stencil() once we have created & attached the
diff --git a/src/cmd/compile/internal/noder/types.go b/src/cmd/compile/internal/noder/types.go
index 541ed68ef3..c9f7c2bbe4 100644
--- a/src/cmd/compile/internal/noder/types.go
+++ b/src/cmd/compile/internal/noder/types.go
@@ -30,21 +30,11 @@ func (g *irgen) pkg(pkg *types2.Package) *types.Pkg {
 // typ converts a types2.Type to a types.Type, including caching of previously
 // translated types.
 func (g *irgen) typ(typ types2.Type) *types.Type {
+	// Defer the CheckSize calls until we have fully-defined a
+	// (possibly-recursive) top-level type.
+	types.DeferCheckSize()
 	res := g.typ1(typ)
-
-	// Calculate the size for all concrete types seen by the frontend. The old
-	// typechecker calls CheckSize() a lot, and we want to eliminate calling
-	// it eventually, so we should do it here instead. We only call it for
-	// top-level types (i.e. we do it here rather in typ1), to make sure that
-	// recursive types have been fully constructed before we call CheckSize.
-	if res != nil && !res.IsUntyped() && !res.IsFuncArgStruct() && !res.HasTParam() {
-		types.CheckSize(res)
-		if res.IsPtr() {
-			// Pointers always have their size set, even though their element
-			// may not have its size set.
-			types.CheckSize(res.Elem())
-		}
-	}
+	types.ResumeCheckSize()
 	return res
 }
 
@@ -59,6 +49,12 @@ func (g *irgen) typ1(typ types2.Type) *types.Type {
 	res, ok := g.typs[typ]
 	if !ok {
 		res = g.typ0(typ)
+		// Calculate the size for all concrete types seen by the frontend.
+		// This is the replacement for the CheckSize() calls in the types1
+		// typechecker. These will be deferred until the top-level g.typ().
+		if res != nil && !res.IsUntyped() && !res.IsFuncArgStruct() && !res.HasTParam() {
+			types.CheckSize(res)
+		}
 		g.typs[typ] = res
 	}
 	return res