diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index e235dd57922..57e8476099e 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -79,8 +79,6 @@ type reader struct {
 
 	p *pkgReader
 
-	ext *reader
-
 	dict *readerDict
 
 	// TODO(mdempsky): The state below is all specific to reading
@@ -586,10 +584,10 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 	dict := pr.objDictIdx(sym, idx, implicits, explicits)
 
 	r := pr.newReader(relocObj, idx, syncObject1)
-	r.ext = pr.newReader(relocObjExt, idx, syncObject1)
+	rext := pr.newReader(relocObjExt, idx, syncObject1)
 
 	r.dict = dict
-	r.ext.dict = dict
+	rext.dict = dict
 
 	sym = r.mangle(sym)
 	if !sym.IsBlank() && sym.Def != nil {
@@ -642,7 +640,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 		name.Func = ir.NewFunc(r.pos())
 		name.Func.Nname = name
 
-		r.ext.funcExt(name)
+		rext.funcExt(name)
 		return name
 
 	case objType:
@@ -651,7 +649,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 		setType(name, typ)
 
 		// Important: We need to do this before SetUnderlying.
-		r.ext.typeExt(name)
+		rext.typeExt(name)
 
 		// We need to defer CheckSize until we've called SetUnderlying to
 		// handle recursive types.
@@ -661,7 +659,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 
 		methods := make([]*types.Field, r.len())
 		for i := range methods {
-			methods[i] = r.method()
+			methods[i] = r.method(rext)
 		}
 		if len(methods) != 0 {
 			typ.Methods().Set(methods)
@@ -674,7 +672,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 	case objVar:
 		name := do(ir.ONAME, false)
 		setType(name, r.typ())
-		r.ext.varExt(name)
+		rext.varExt(name)
 		return name
 	}
 }
@@ -756,7 +754,7 @@ func (r *reader) typeParamNames() {
 	}
 }
 
-func (r *reader) method() *types.Field {
+func (r *reader) method(rext *reader) *types.Field {
 	r.sync(syncMethod)
 	pos := r.pos()
 	pkg, sym := r.selector()
@@ -772,7 +770,7 @@ func (r *reader) method() *types.Field {
 	name.Func = ir.NewFunc(r.pos())
 	name.Func.Nname = name
 
-	r.ext.funcExt(name)
+	rext.funcExt(name)
 
 	meth := types.NewField(name.Func.Pos(), sym, typ)
 	meth.Nname = name
diff --git a/src/cmd/compile/internal/noder/unified.go b/src/cmd/compile/internal/noder/unified.go
index 02f64d00ac9..eff2eeaeff5 100644
--- a/src/cmd/compile/internal/noder/unified.go
+++ b/src/cmd/compile/internal/noder/unified.go
@@ -106,7 +106,6 @@ func unified(noders []*noder) {
 	readPackage(localPkgReader, types.LocalPkg)
 
 	r := localPkgReader.newReader(relocMeta, privateRootIdx, syncPrivate)
-	r.ext = r
 	r.pkgInit(types.LocalPkg, target)
 
 	// Type-check any top-level assignments. We ignore non-assignments
@@ -190,7 +189,6 @@ func writePkgStub(noders []*noder) string {
 
 	{
 		w := privateRootWriter
-		w.ext = w
 		w.pkgInit(noders)
 		w.flush()
 	}
diff --git a/src/cmd/compile/internal/noder/writer.go b/src/cmd/compile/internal/noder/writer.go
index 694035b73fe..e1413da1d85 100644
--- a/src/cmd/compile/internal/noder/writer.go
+++ b/src/cmd/compile/internal/noder/writer.go
@@ -75,14 +75,6 @@ type writer struct {
 
 	encoder
 
-	// For writing out object descriptions, ext points to the extension
-	// writer for where we can write the compiler's private extension
-	// details for the object.
-	//
-	// TODO(mdempsky): This is a little hacky, but works easiest with
-	// the way things are currently.
-	ext *writer
-
 	// TODO(mdempsky): We should be able to prune localsIdx whenever a
 	// scope closes, and then maybe we can just use the same map for
 	// storing the TypeParams too (as their TypeName instead).
@@ -504,21 +496,21 @@ func (pw *pkgWriter) objIdx(obj types2.Object) int {
 	}
 
 	w := pw.newWriter(relocObj, syncObject1)
-	w.ext = pw.newWriter(relocObjExt, syncObject1)
+	wext := pw.newWriter(relocObjExt, syncObject1)
 	wname := pw.newWriter(relocName, syncObject1)
 	wdict := pw.newWriter(relocObjDict, syncObject1)
 
 	pw.globalsIdx[obj] = w.idx // break cycles
-	assert(w.ext.idx == w.idx)
+	assert(wext.idx == w.idx)
 	assert(wname.idx == w.idx)
 	assert(wdict.idx == w.idx)
 
 	w.dict = dict
-	w.ext.dict = dict
+	wext.dict = dict
 
-	code := w.doObj(obj)
+	code := w.doObj(wext, obj)
 	w.flush()
-	w.ext.flush()
+	wext.flush()
 
 	wname.qualifiedIdent(obj)
 	wname.code(code)
@@ -530,7 +522,7 @@ func (pw *pkgWriter) objIdx(obj types2.Object) int {
 	return w.idx
 }
 
-func (w *writer) doObj(obj types2.Object) codeObj {
+func (w *writer) doObj(wext *writer, obj types2.Object) codeObj {
 	if obj.Pkg() != w.p.curpkg {
 		return objStub
 	}
@@ -555,7 +547,7 @@ func (w *writer) doObj(obj types2.Object) codeObj {
 		w.typeParamNames(sig.TypeParams())
 		w.signature(sig)
 		w.pos(decl)
-		w.ext.funcExt(obj)
+		wext.funcExt(obj)
 		return objFunc
 
 	case *types2.TypeName:
@@ -573,12 +565,12 @@ func (w *writer) doObj(obj types2.Object) codeObj {
 
 		w.pos(obj)
 		w.typeParamNames(named.TypeParams())
-		w.ext.typeExt(obj)
+		wext.typeExt(obj)
 		w.typExpr(decl.Type)
 
 		w.len(named.NumMethods())
 		for i := 0; i < named.NumMethods(); i++ {
-			w.method(named.Method(i))
+			w.method(wext, named.Method(i))
 		}
 
 		return objType
@@ -586,7 +578,7 @@ func (w *writer) doObj(obj types2.Object) codeObj {
 	case *types2.Var:
 		w.pos(obj)
 		w.typ(obj.Type())
-		w.ext.varExt(obj)
+		wext.varExt(obj)
 		return objVar
 	}
 }
@@ -648,7 +640,7 @@ func (w *writer) typeParamNames(tparams *types2.TypeParamList) {
 	}
 }
 
-func (w *writer) method(meth *types2.Func) {
+func (w *writer) method(wext *writer, meth *types2.Func) {
 	decl, ok := w.p.funDecls[meth]
 	assert(ok)
 	sig := meth.Type().(*types2.Signature)
@@ -661,7 +653,7 @@ func (w *writer) method(meth *types2.Func) {
 	w.signature(sig)
 
 	w.pos(decl) // XXX: Hack to workaround linker limitations.
-	w.ext.funcExt(meth)
+	wext.funcExt(meth)
 }
 
 // qualifiedIdent writes out the name of an object declared at package