various: we don't cast, we convert

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5437142

src/pkg/compress/bzip2/bit_reader.go

@@ -20,7 +20,7 @@ type bitReader struct {
 	err  error
 }
 
-// bitReader needs to read bytes from an io.Reader. We attempt to cast the
+// bitReader needs to read bytes from an io.Reader. We attempt to convert the
 // given io.Reader to this interface and, if it doesn't already fit, we wrap in
 // a bufio.Reader.
 type byteReader interface {

src/pkg/exp/ssh/session_test.go

@@ -61,7 +61,7 @@ func dial(t *testing.T) *ClientConn {
 					WantReply bool
 					Status    uint32
 				}
-				// TODO(dfc) casting to the concrete type should not be
+				// TODO(dfc) converting to the concrete type should not be
 				// necessary to send a packet.
 				msg := exitMsg{
 					PeersId:   ch.(*channel).theirId,

src/pkg/fmt/doc.go

@@ -103,7 +103,7 @@
 	To avoid recursion in cases such as
 		type X string
 		func (x X) String() string { return Sprintf("<%s>", x) }
-	cast the value before recurring:
+	convert the value before recurring:
 		func (x X) String() string { return Sprintf("<%s>", string(x)) }
 
 	Format errors:

src/pkg/unicode/graphic.go

@@ -32,8 +32,8 @@ var PrintRanges = []*RangeTable{
 // Such characters include letters, marks, numbers, punctuation, symbols, and
 // spaces, from categories L, M, N, P, S, Zs.
 func IsGraphic(r rune) bool {
-	// We cast to uint32 to avoid the extra test for negative,
-	// and in the index we cast to uint8 to avoid the range check.
+	// We convert to uint32 to avoid the extra test for negative,
+	// and in the index we convert to uint8 to avoid the range check.
 	if uint32(r) <= MaxLatin1 {
 		return properties[uint8(r)]&pg != 0
 	}