diff --git a/cl/import.go b/cl/import.go
index 970758a2..171ea4d9 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -65,15 +65,19 @@ func (p *pkgSymInfo) addSym(fset *token.FileSet, pos token.Pos, fullName, inPkgN
 }
 
 func (p *pkgSymInfo) initLinknames(ctx *context) {
+	sep := []byte{'\n'}
+	commentPrefix := []byte{'/', '/'}
 	for file, b := range p.files {
-		lines := bytes.Split(b, []byte{'\n'})
+		lines := bytes.Split(b, sep)
 		for _, line := range lines {
-			ctx.initLinkname(string(line), func(inPkgName string) (fullName string, isVar, ok bool) {
-				if sym, ok := p.syms[inPkgName]; ok && file == sym.file {
-					return sym.fullName, sym.isVar, true
-				}
-				return
-			})
+			if bytes.HasPrefix(line, commentPrefix) {
+				ctx.initLinkname(string(line), func(inPkgName string) (fullName string, isVar, ok bool) {
+					if sym, ok := p.syms[inPkgName]; ok && file == sym.file {
+						return sym.fullName, sym.isVar, true
+					}
+					return
+				})
+			}
 		}
 	}
 }
diff --git a/internal/build/build.go b/internal/build/build.go
index fdbc92bb..f1f260f0 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -33,6 +33,7 @@ import (
 
 	"github.com/goplus/llgo/cl"
 	"github.com/goplus/llgo/internal/packages"
+	"github.com/goplus/llgo/internal/typepatch"
 	"github.com/goplus/llgo/xtool/clang"
 	"github.com/goplus/llgo/xtool/env"
 
@@ -94,6 +95,7 @@ func Do(args []string, conf *Config) {
 	cfg := &packages.Config{
 		Mode:       loadSyntax | packages.NeedDeps | packages.NeedModule | packages.NeedExportFile,
 		BuildFlags: flags,
+		Fset:       token.NewFileSet(),
 	}
 
 	llssa.Initialize(llssa.InitAll)
@@ -365,11 +367,15 @@ func buildPkg(prog llssa.Program, aPkg *aPackage, mode Mode, verbose bool) {
 		pkg.ExportFile = ""
 		return
 	}
+	altSSA := aPkg.AltSSA
 	syntax := pkg.Syntax
 	if altPkg := aPkg.AltPkg; altPkg != nil {
 		syntax = append(syntax, altPkg.Syntax...)
+		if altSSA != nil {
+			altSSA.Pkg = typepatch.Pkg(pkg.Types, altPkg.Types)
+		}
 	}
-	ret, err := cl.NewPackageEx(prog, aPkg.SSA, aPkg.AltSSA, syntax)
+	ret, err := cl.NewPackageEx(prog, aPkg.SSA, altSSA, syntax)
 	check(err)
 	if needLLFile(mode) {
 		pkg.ExportFile += ".ll"
@@ -421,8 +427,6 @@ func allPkgs(imp importer, initial []*packages.Package, mode ssa.BuilderMode) (p
 					altPkgPath := "github.com/goplus/llgo/internal/lib/" + p.PkgPath
 					if altPkg = imp(altPkgPath); altPkg != nil {
 						altSSA = createAltSSAPkg(prog, altPkg)
-						altSSA.Pkg = p.Types
-						// TODO(xsw): merge p.Types and altPkg.Types
 					}
 				}
 			}
diff --git a/internal/typepatch/patch.go b/internal/typepatch/patch.go
new file mode 100644
index 00000000..ae17a2a5
--- /dev/null
+++ b/internal/typepatch/patch.go
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package typepatch
+
+import (
+	"go/token"
+	"go/types"
+	"unsafe"
+)
+
+type typesScope struct {
+	parent   *types.Scope
+	children []*types.Scope
+	number   int
+	elems    map[string]types.Object // TODO(xsw): ensure offset of elems
+	pos, end token.Pos
+	comment  string
+	isFunc   bool
+}
+
+type object struct {
+	parent *types.Scope
+	pos    token.Pos
+	pkg    *types.Package // TODO(xsw): ensure offset of pkg
+	unused [8]byte
+}
+
+type iface struct {
+	tab  unsafe.Pointer
+	data unsafe.Pointer
+}
+
+func setPkg(o types.Object, pkg *types.Package) {
+	data := (*iface)(unsafe.Pointer(&o)).data
+	(*object)(data).pkg = pkg
+}
+
+func setObject(scope *types.Scope, name string, o types.Object) {
+	s := (*typesScope)(unsafe.Pointer(scope))
+	s.elems[name] = o
+}
+
+func Pkg(pkg, alt *types.Package) *types.Package {
+	scope := pkg.Scope()
+	altScope := alt.Scope()
+	for _, name := range altScope.Names() {
+		o := altScope.Lookup(name)
+		setPkg(o, pkg)
+		setObject(scope, name, o)
+	}
+	return pkg
+}