diff --git a/internal/fetchdatasource/fetchdatasource.go b/internal/fetchdatasource/fetchdatasource.go
index 69f803e..fe2eacc 100644
--- a/internal/fetchdatasource/fetchdatasource.go
+++ b/internal/fetchdatasource/fetchdatasource.go
@@ -181,10 +181,12 @@
 		Path:       path,
 		ModuleInfo: module.ModuleInfo,
 	}
-	if u := findUnit(module, path); u != nil {
-		um.Name = u.Name
-		um.IsRedistributable = u.IsRedistributable
+	u := findUnit(module, path)
+	if u == nil {
+		return nil, derrors.NotFound
 	}
+	um.Name = u.Name
+	um.IsRedistributable = u.IsRedistributable
 	return um, nil
 }
 
diff --git a/internal/fetchdatasource/fetchdatasource_test.go b/internal/fetchdatasource/fetchdatasource_test.go
index a1fc95c..995dfad 100644
--- a/internal/fetchdatasource/fetchdatasource_test.go
+++ b/internal/fetchdatasource/fetchdatasource_test.go
@@ -309,10 +309,9 @@
 			wantErr:    derrors.NotFound,
 		},
 		{
-			fullPath:        "foo.com/bar/baz",
-			modulePath:      "foo.com/bar",
-			wantModulePath:  "foo.com/bar/v3",
-			wantPackagePath: "foo.com/bar/v3",
+			fullPath:   "foo.com/bar/baz",
+			modulePath: "foo.com/bar",
+			wantErr:    derrors.NotFound,
 		},
 		{
 			fullPath:        "incompatible.com/bar",
@@ -424,6 +423,12 @@
 			modulePath: stdlib.ModulePath,
 			wantErr:    derrors.InvalidArgument,
 		},
+		{
+			// Module is known but path isn't in it.
+			path:       "github.com/my/module/unk",
+			modulePath: "github.com/my/module",
+			wantErr:    derrors.NotFound,
+		},
 	} {
 		t.Run(test.path, func(t *testing.T) {
 			got, err := ds.GetUnitMeta(ctx, test.path, test.modulePath, fetch.LocalVersion)