Merge pull request #349 from xushiwei/imp

MarkForceUsed

import.go

@@ -67,6 +67,11 @@ func (p PkgRef) TryRef(name string) Ref {
 	return p.Types.Scope().Lookup(name)
 }
 
+// MarkForceUsed marks to import a package always (i.e. `import _ pkgPath`).
+func (p PkgRef) MarkForceUsed(pkg *Package) {
+	pkg.file.forceImport(p.Types.Path())
+}
+
 // Deprecated: EnsureImported is nothing to do now.
 func (p PkgRef) EnsureImported() {
 }

package_test.go

@@ -2596,6 +2596,19 @@ func main() {
 `)
 }
 
+func TestImportForceUsed2(t *testing.T) {
+	pkg := newMainPackage()
+	pkg.Import("fmt").MarkForceUsed(pkg)
+	pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg).End()
+	domTest(t, pkg, `package main
+
+import _ "fmt"
+
+func main() {
+}
+`)
+}
+
 func TestImportAnyWhere(t *testing.T) {
 	pkg := newMainPackage()