diff --git a/src/lib/bufio_test.go b/src/lib/bufio_test.go
index 4afad83404c..ef97bc46ec4 100644
--- a/src/lib/bufio_test.go
+++ b/src/lib/bufio_test.go
@@ -135,7 +135,7 @@ func readBytes(buf *BufRead) string {
 		nb++;
 	}
 	// BUG return string(b[0:nb]) ?
-	return string(b)[0:nb]
+	return string(b[0:nb])
 }
 
 // Call Read to accumulate the text of a file
diff --git a/src/lib/fmt/format.go b/src/lib/fmt/format.go
index 14c5043ac7a..ce5050371f9 100644
--- a/src/lib/fmt/format.go
+++ b/src/lib/fmt/format.go
@@ -222,7 +222,7 @@ func (f *Fmt) integer(a int64, base uint, is_signed bool, digits *string) string
 		buf[i] = ' ';
 		i--;
 	}
-	return string(buf)[i+1:nByte];
+	return string(buf[i+1:nByte]);
 }
 
 // Fmt_d64 formats an int64 in decimal.
diff --git a/src/lib/syscall/errstr_darwin.go b/src/lib/syscall/errstr_darwin.go
index 1ea3576019b..abb79b88429 100644
--- a/src/lib/syscall/errstr_darwin.go
+++ b/src/lib/syscall/errstr_darwin.go
@@ -231,7 +231,7 @@ func str(val int64) string {  // do it here rather than with fmt to avoid depend
 		val /= 10;
 	}
 	buf[i] = byte(val + '0');
-	return string(buf)[i:len(buf)];
+	return string(buf[i:len(buf)]);
 }
 
 func Errstr(errno int64) string {
diff --git a/src/lib/syscall/errstr_linux.go b/src/lib/syscall/errstr_linux.go
index 61ac4b56e1b..47b5c6462fd 100644
--- a/src/lib/syscall/errstr_linux.go
+++ b/src/lib/syscall/errstr_linux.go
@@ -281,7 +281,7 @@ func str(val int64) string {  // do it here rather than with fmt to avoid depend
 		val /= 10;
 	}
 	buf[i] = byte(val + '0');
-	return string(buf)[i:len(buf)];
+	return string(buf[i:len(buf)]);
 }
 
 func Errstr(errno int64) string {