support import shadowing

mockgen/internal/tests/import_shadowing/foo/foo.go

@@ -0,0 +1,3 @@
+package foo
+
+type MyInt int

mockgen/internal/tests/import_shadowing/import.go

@@ -0,0 +1,11 @@
+package import_shadowing
+
+import (
+	"go.uber.org/mock/mockgen/internal/tests/import_shadowing/foo"
+)
+
+//go:generate mockgen -destination mock.go -source import.go -package import_shadowing . Bar
+
+type Bar interface {
+	Hoge(foo string) foo.MyInt
+}

mockgen/mockgen.go

@@ -363,6 +363,16 @@ func (g *generator) Generate(pkg *model.Package, outputPkgName string, outputPac
 
 	g.packageMap = make(map[string]string, len(im))
 	localNames := make(map[string]bool, len(im))
+	paramNamesInterfaces := make(map[string]struct{}, 0)
+	for _, intf := range pkg.Interfaces {
+		for _, m := range intf.Methods {
+			for _, i := range m.In {
+				if i.Name != "" {
+					paramNamesInterfaces[i.Name] = struct{}{}
+				}
+			}
+		}
+	}
 	for _, pth := range sortedPaths {
 		base, ok := packagesName[pth]
 		if !ok {
@@ -386,6 +396,10 @@ func (g *generator) Generate(pkg *model.Package, outputPkgName string, outputPac
 			i++
 		}
 
+		if _, isImportShadowing := paramNamesInterfaces[pkgName]; isImportShadowing {
+			pkgName = base + "Pkg"
+		}
+
 		// Avoid importing package if source pkg == output pkg
 		if pth == pkg.PkgPath && outputPackagePath == pkg.PkgPath {
 			continue