diff --git a/src/cmd/go/internal/modload/build.go b/src/cmd/go/internal/modload/build.go
index f49b52df56..b9abb0b93c 100644
--- a/src/cmd/go/internal/modload/build.go
+++ b/src/cmd/go/internal/modload/build.go
@@ -13,7 +13,6 @@ import (
 	"internal/goroot"
 	"os"
 	"path/filepath"
-	"runtime/debug"
 	"strings"
 
 	"cmd/go/internal/base"
@@ -312,9 +311,6 @@ func mustFindModule(target, path string) module.Version {
 		return Target
 	}
 
-	if printStackInDie {
-		debug.PrintStack()
-	}
 	base.Fatalf("build %v: cannot find module for path %v", target, path)
 	panic("unreachable")
 }
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index e1b784860b..1fcc53735c 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -16,7 +16,6 @@ import (
 	"os"
 	"path"
 	"path/filepath"
-	"runtime/debug"
 	"strconv"
 	"strings"
 
@@ -330,16 +329,7 @@ func ModFilePath() string {
 	return filepath.Join(modRoot, "go.mod")
 }
 
-// printStackInDie causes die to print a stack trace.
-//
-// It is enabled by the testgo tag, and helps to diagnose paths that
-// unexpectedly require a main module.
-var printStackInDie = false
-
 func die() {
-	if printStackInDie {
-		debug.PrintStack()
-	}
 	if cfg.Getenv("GO111MODULE") == "off" {
 		base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
 	}
diff --git a/src/cmd/go/internal/modload/testgo.go b/src/cmd/go/internal/modload/testgo.go
deleted file mode 100644
index 6b34f5be39..0000000000
--- a/src/cmd/go/internal/modload/testgo.go
+++ /dev/null
@@ -1,11 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build testgo
-
-package modload
-
-func init() {
-	printStackInDie = true
-}