diff --git a/src/internal/coverage/decodecounter/decodecounterfile.go b/src/internal/coverage/decodecounter/decodecounterfile.go
index 8a4c302275d..8a905d9c341 100644
--- a/src/internal/coverage/decodecounter/decodecounterfile.go
+++ b/src/internal/coverage/decodecounter/decodecounterfile.go
@@ -63,7 +63,7 @@ func NewCounterDataReader(fn string, rs io.ReadSeeker) (*CounterDataReader, erro
 	}
 	// Seek back to just past the file header.
 	hsz := int64(unsafe.Sizeof(cdr.hdr))
-	if _, err := cdr.mr.Seek(hsz, os.SEEK_SET); err != nil {
+	if _, err := cdr.mr.Seek(hsz, io.SeekStart); err != nil {
 		return nil, err
 	}
 	// Read preamble for first segment.
diff --git a/src/internal/coverage/decodemeta/decodefile.go b/src/internal/coverage/decodemeta/decodefile.go
index dd602c5d8ac..6580dd54022 100644
--- a/src/internal/coverage/decodemeta/decodefile.go
+++ b/src/internal/coverage/decodemeta/decodefile.go
@@ -213,7 +213,7 @@ func (r *CoverageMetaFileReader) GetPackagePayload(pkIdx uint32, payloadbuf []by
 		payload = make([]byte, 0, len)
 	}
 	payload = append(payload, make([]byte, len)...)
-	if _, err := r.f.Seek(int64(off), os.SEEK_SET); err != nil {
+	if _, err := r.f.Seek(int64(off), io.SeekStart); err != nil {
 		return nil, err
 	}
 	if _, err := io.ReadFull(r.f, payload); err != nil {
diff --git a/src/internal/coverage/encodemeta/encode.go b/src/internal/coverage/encodemeta/encode.go
index 1bc950637f6..686042036a5 100644
--- a/src/internal/coverage/encodemeta/encode.go
+++ b/src/internal/coverage/encodemeta/encode.go
@@ -175,7 +175,7 @@ func (b *CoverageMetaDataBuilder) Emit(w io.WriteSeeker) ([16]byte, error) {
 
 	// Back-patch the length.
 	totalLength := uint32(off)
-	if _, err := w.Seek(0, os.SEEK_SET); err != nil {
+	if _, err := w.Seek(0, io.SeekStart); err != nil {
 		return digest, err
 	}
 	b.wrUint32(w, totalLength)
diff --git a/src/internal/coverage/slicewriter/slicewriter.go b/src/internal/coverage/slicewriter/slicewriter.go
index e606db901b0..3522bf5770e 100644
--- a/src/internal/coverage/slicewriter/slicewriter.go
+++ b/src/internal/coverage/slicewriter/slicewriter.go
@@ -6,7 +6,7 @@ package slicewriter
 
 import (
 	"fmt"
-	"os"
+	"io"
 )
 
 // WriteSeeker is a helper object that implements the io.WriteSeeker
@@ -37,20 +37,20 @@ func (sws *WriteSeeker) Write(p []byte) (n int, err error) {
 // the slice will result in an error.
 func (sws *WriteSeeker) Seek(offset int64, whence int) (int64, error) {
 	switch whence {
-	case os.SEEK_SET:
+	case io.SeekStart:
 		if sws.off != offset && (offset < 0 || offset >= int64(len(sws.payload))) {
 			return 0, fmt.Errorf("invalid seek: new offset %d (out of range [0 %d]", offset, len(sws.payload))
 		}
 		sws.off = offset
 		return offset, nil
-	case os.SEEK_CUR:
+	case io.SeekCurrent:
 		newoff := sws.off + offset
 		if newoff != sws.off && (newoff < 0 || newoff >= int64(len(sws.payload))) {
 			return 0, fmt.Errorf("invalid seek: new offset %d (out of range [0 %d]", newoff, len(sws.payload))
 		}
 		sws.off += offset
 		return sws.off, nil
-	case os.SEEK_END:
+	case io.SeekEnd:
 		newoff := int64(len(sws.payload)) + offset
 		if newoff != sws.off && (newoff < 0 || newoff >= int64(len(sws.payload))) {
 			return 0, fmt.Errorf("invalid seek: new offset %d (out of range [0 %d]", newoff, len(sws.payload))