diff --git a/go.mod b/go.mod
index b276b3776..a59ad507c 100644
--- a/go.mod
+++ b/go.mod
@@ -55,7 +55,7 @@ require (
 	github.com/weaveworks/libgitops v0.0.0-20200611103311-2c871bbbbf0c
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
 	golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f
-	golang.org/x/tools v0.0.0-20210102185154-773b96fafca2 // indirect
+	golang.org/x/tools v0.0.0-20210108195828-e2f9c7f1fc8e // indirect
 	gotest.tools v2.2.0+incompatible
 	k8s.io/apimachinery v0.18.3
 	k8s.io/code-generator v0.19.2
diff --git a/go.sum b/go.sum
index b05fa466f..8c5eae750 100644
--- a/go.sum
+++ b/go.sum
@@ -1005,8 +1005,8 @@ golang.org/x/tools v0.0.0-20191216052735-49a3e744a425 h1:VvQyQJN0tSuecqgcIxMWnnf
 golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/tools v0.0.0-20200616133436-c1934b75d054 h1:HHeAlu5H9b71C+Fx0K+1dGgVFN1DM1/wz4aoGOA5qS8=
 golang.org/x/tools v0.0.0-20200616133436-c1934b75d054/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
-golang.org/x/tools v0.0.0-20210102185154-773b96fafca2 h1:crjwvdT+rSAILpNOKhk/BNmefsucqGTeeRX2YBK/6Jg=
-golang.org/x/tools v0.0.0-20210102185154-773b96fafca2/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
+golang.org/x/tools v0.0.0-20210108195828-e2f9c7f1fc8e h1:Z2uDrs8MyXUWJbwGc4V+nGjV4Ygo+oubBbWSVQw21/I=
+golang.org/x/tools v0.0.0-20210108195828-e2f9c7f1fc8e/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
diff --git a/vendor/golang.org/x/tools/go/ast/astutil/util.go b/vendor/golang.org/x/tools/go/ast/astutil/util.go
index 763062982..919d5305a 100644
--- a/vendor/golang.org/x/tools/go/ast/astutil/util.go
+++ b/vendor/golang.org/x/tools/go/ast/astutil/util.go
@@ -1,3 +1,7 @@
+// Copyright 2015 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.
+
 package astutil
 
 import "go/ast"
diff --git a/vendor/golang.org/x/tools/imports/forward.go b/vendor/golang.org/x/tools/imports/forward.go
index a4e40adba..8be18a66b 100644
--- a/vendor/golang.org/x/tools/imports/forward.go
+++ b/vendor/golang.org/x/tools/imports/forward.go
@@ -1,3 +1,7 @@
+// Copyright 2019 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.
+
 // Package imports implements a Go pretty-printer (like package "go/format")
 // that also adds or removes import statements as necessary.
 package imports // import "golang.org/x/tools/imports"
diff --git a/vendor/golang.org/x/tools/internal/gocommand/version.go b/vendor/golang.org/x/tools/internal/gocommand/version.go
index 60d45ac0e..0cebac6e6 100644
--- a/vendor/golang.org/x/tools/internal/gocommand/version.go
+++ b/vendor/golang.org/x/tools/internal/gocommand/version.go
@@ -16,9 +16,20 @@ func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
 	inv.Verb = "list"
 	inv.Args = []string{"-e", "-f", `{{context.ReleaseTags}}`}
 	inv.Env = append(append([]string{}, inv.Env...), "GO111MODULE=off")
-	// Unset any unneeded flags.
+	// Unset any unneeded flags, and remove them from BuildFlags, if they're
+	// present.
 	inv.ModFile = ""
 	inv.ModFlag = ""
+	var buildFlags []string
+	for _, flag := range inv.BuildFlags {
+		// Flags can be prefixed by one or two dashes.
+		f := strings.TrimPrefix(strings.TrimPrefix(flag, "-"), "-")
+		if strings.HasPrefix(f, "mod=") || strings.HasPrefix(f, "modfile=") {
+			continue
+		}
+		buildFlags = append(buildFlags, flag)
+	}
+	inv.BuildFlags = buildFlags
 	stdoutBytes, err := r.Run(ctx, inv)
 	if err != nil {
 		return 0, err
diff --git a/vendor/golang.org/x/tools/internal/imports/mod.go b/vendor/golang.org/x/tools/internal/imports/mod.go
index ce3269a43..901449a82 100644
--- a/vendor/golang.org/x/tools/internal/imports/mod.go
+++ b/vendor/golang.org/x/tools/internal/imports/mod.go
@@ -1,3 +1,7 @@
+// Copyright 2019 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.
+
 package imports
 
 import (
diff --git a/vendor/golang.org/x/tools/internal/imports/mod_cache.go b/vendor/golang.org/x/tools/internal/imports/mod_cache.go
index 5b4f03acc..18dada495 100644
--- a/vendor/golang.org/x/tools/internal/imports/mod_cache.go
+++ b/vendor/golang.org/x/tools/internal/imports/mod_cache.go
@@ -1,3 +1,7 @@
+// Copyright 2019 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.
+
 package imports
 
 import (
diff --git a/vendor/modules.txt b/vendor/modules.txt
index ddeed6c97..f58234efa 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -527,7 +527,7 @@ golang.org/x/text/transform
 golang.org/x/text/unicode/bidi
 golang.org/x/text/unicode/norm
 golang.org/x/text/width
-# golang.org/x/tools v0.0.0-20210102185154-773b96fafca2
+# golang.org/x/tools v0.0.0-20210108195828-e2f9c7f1fc8e
 ## explicit
 golang.org/x/tools/go/ast/astutil
 golang.org/x/tools/imports