diff --git a/go/ir/source_test.go b/go/ir/source_test.go
index 3810a314b..3346ebeb8 100644
--- a/go/ir/source_test.go
+++ b/go/ir/source_test.go
@@ -15,7 +15,6 @@ import (
 	"go/parser"
 	"go/token"
 	"go/types"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -37,7 +36,7 @@ func TestObjValueLookup(t *testing.T) {
 	}
 
 	conf := loader.Config{ParserMode: parser.ParseComments}
-	src, err := ioutil.ReadFile(filepath.Join(analysistest.TestData(), "objlookup.go"))
+	src, err := os.ReadFile(filepath.Join(analysistest.TestData(), "objlookup.go"))
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/staticcheck/sa1003/testdata/go1.0/CheckEncodingBinary/CheckEncodingBinary.go b/staticcheck/sa1003/testdata/go1.0/CheckEncodingBinary/CheckEncodingBinary.go
index b956d2026..ef9d2f84e 100644
--- a/staticcheck/sa1003/testdata/go1.0/CheckEncodingBinary/CheckEncodingBinary.go
+++ b/staticcheck/sa1003/testdata/go1.0/CheckEncodingBinary/CheckEncodingBinary.go
@@ -3,7 +3,6 @@ package pkg
 import (
 	"encoding/binary"
 	"io"
-	"io/ioutil"
 	"log"
 )
 
@@ -40,21 +39,21 @@ func fn() {
 	var x13 []byte
 	var x14 *[]byte
 	var x15 T6
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x1)) //@ diag(`cannot be used with binary.Write`)
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x2))
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x3)) //@ diag(`cannot be used with binary.Write`)
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x4))
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x5)) //@ diag(`cannot be used with binary.Write`)
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x6))
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x7))
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x8))  //@ diag(`cannot be used with binary.Write`)
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x9))  //@ diag(`cannot be used with binary.Write`)
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x10)) //@ diag(`cannot be used with binary.Write`)
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x11))
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, &x13))
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, &x14)) //@ diag(`cannot be used with binary.Write`)
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x15))
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, &x15))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x1)) //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x2))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x3)) //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x4))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x5)) //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x6))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x7))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x8))  //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x9))  //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x10)) //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x11))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, &x13))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, &x14)) //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x15))
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, &x15))
 	log.Println(binary.Write(fn2())) //@ diag(`cannot be used with binary.Write`)
 	log.Println(binary.Write(fn3()))
 }
diff --git a/staticcheck/sa1003/testdata/go1.7/CheckEncodingBinary/CheckEncodingBinary.go b/staticcheck/sa1003/testdata/go1.7/CheckEncodingBinary/CheckEncodingBinary.go
index 82b89e915..d874996ef 100644
--- a/staticcheck/sa1003/testdata/go1.7/CheckEncodingBinary/CheckEncodingBinary.go
+++ b/staticcheck/sa1003/testdata/go1.7/CheckEncodingBinary/CheckEncodingBinary.go
@@ -2,11 +2,11 @@ package pkg
 
 import (
 	"encoding/binary"
-	"io/ioutil"
+	"io"
 	"log"
 )
 
 func fn() {
 	var x bool
-	log.Println(binary.Write(ioutil.Discard, binary.LittleEndian, x)) //@ diag(`cannot be used with binary.Write`)
+	log.Println(binary.Write(io.Discard, binary.LittleEndian, x)) //@ diag(`cannot be used with binary.Write`)
 }
diff --git a/staticcheck/sa1003/testdata/go1.8/CheckEncodingBinary/CheckEncodingBinary.go b/staticcheck/sa1003/testdata/go1.8/CheckEncodingBinary/CheckEncodingBinary.go
index 61bc823f1..2046743b4 100644
--- a/staticcheck/sa1003/testdata/go1.8/CheckEncodingBinary/CheckEncodingBinary.go
+++ b/staticcheck/sa1003/testdata/go1.8/CheckEncodingBinary/CheckEncodingBinary.go
@@ -2,10 +2,10 @@ package pkg
 
 import (
 	"encoding/binary"
-	"io/ioutil"
+	"io"
 )
 
 func fn() {
 	var x bool
-	binary.Write(ioutil.Discard, binary.LittleEndian, x)
+	binary.Write(io.Discard, binary.LittleEndian, x)
 }
diff --git a/unused/testdata/src/example.com/exported_method_test/exported_method_test.go b/unused/testdata/src/example.com/exported_method_test/exported_method_test.go
index 482541df3..f0f276ce6 100644
--- a/unused/testdata/src/example.com/exported_method_test/exported_method_test.go
+++ b/unused/testdata/src/example.com/exported_method_test/exported_method_test.go
@@ -3,7 +3,6 @@ package pkg
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"testing"
 )
 
@@ -21,7 +20,7 @@ func (rs *countReadSeeker) Read(buf []byte) (int, error) { //@ used_test("Read",
 func TestFoo(t *testing.T) { //@ used_test("TestFoo", true), used_test("t", true)
 	r := bytes.NewReader([]byte("Hello, world!")) //@ used_test("r", true)
 	cr := &countReadSeeker{ReadSeeker: r}         //@ used_test("cr", true)
-	ioutil.ReadAll(cr)
+	io.ReadAll(cr)
 	if cr.N != 13 {
 		t.Errorf("got %d, want 13", cr.N)
 	}