diff --git a/src/pkg/io/io.go b/src/pkg/io/io.go
index 7c863c16d32..5187eff70a9 100644
--- a/src/pkg/io/io.go
+++ b/src/pkg/io/io.go
@@ -131,9 +131,9 @@ type ReadWriteSeeker interface {
 
 // ReaderFrom is the interface that wraps the ReadFrom method.
 //
-// ReadFrom reads data from r until EOF. The return value n is the
-// number of bytes read. Any error except io.EOF encountered during
-// the read is also returned.
+// ReadFrom reads data from r until EOF or error.
+// The return value n is the number of bytes read.
+// Any error except io.EOF encountered during the read is also returned.
 //
 // The Copy function uses ReaderFrom if available.
 type ReaderFrom interface {