diff --git a/gopmod/classfile.go b/gopmod/classfile.go
index a23492b..e2b5c56 100644
--- a/gopmod/classfile.go
+++ b/gopmod/classfile.go
@@ -46,41 +46,15 @@ var (
 // -----------------------------------------------------------------------------
 
 func (p *Module) IsClass(ext string) (isProj bool, ok bool) {
-	_, isProj = p.projects[ext]
-	if isProj {
-		ok = true
-		return
+	c, ok := p.projects[ext]
+	if ok {
+		isProj = (ext == c.Ext)
 	}
-	_, ok = p.classes[ext]
 	return
 }
 
 func (p *Module) LookupClass(ext string) (c *Project, ok bool) {
 	c, ok = p.projects[ext]
-	if !ok {
-		c, ok = p.classes[ext]
-	}
-	return
-}
-
-type Kind int
-
-const (
-	KindNone Kind = iota << 1
-	KindWork
-	KindProj
-	KindBoth = KindProj | KindWork
-)
-
-func (p *Module) ClassKind(ext string) (kind Kind) {
-	_, isProj := p.projects[ext]
-	if isProj {
-		kind = KindProj
-	}
-	_, isClass := p.classes[ext]
-	if isClass {
-		kind |= KindWork
-	}
 	return
 }
 
@@ -137,7 +111,7 @@ func (p *Module) registerClassFrom(modVer module.Version, regcls func(c *Project
 func (p *Module) registerClass(c *Project, regcls func(c *Project)) {
 	p.projects[c.Ext] = c
 	for _, w := range c.Works {
-		p.classes[w.Ext] = c
+		p.projects[w.Ext] = c
 	}
 	if regcls != nil {
 		regcls(c)
diff --git a/gopmod/module.go b/gopmod/module.go
index 10d7fe8..8da2a03 100644
--- a/gopmod/module.go
+++ b/gopmod/module.go
@@ -42,8 +42,7 @@ type depmodInfo struct {
 
 type Module struct {
 	modload.Module
-	projects map[string]*Project // project ext -> project
-	classes  map[string]*Project // class ext -> project
+	projects map[string]*Project // ext -> project
 	depmods  []depmodInfo
 }
 
@@ -176,10 +175,9 @@ func getDepMods(mod modload.Module) []depmodInfo {
 
 // New creates a module from a modload.Module instance.
 func New(mod modload.Module) *Module {
+	projects := make(map[string]*Project)
 	depmods := getDepMods(mod)
-	return &Module{projects: make(map[string]*Project),
-		classes: make(map[string]*Project),
-		depmods: depmods, Module: mod}
+	return &Module{projects: projects, depmods: depmods, Module: mod}
 }
 
 // Load loads a module from a local dir.