build: remove dead code

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7877045

src/cmd/go/discovery.go

@@ -48,7 +48,6 @@ func parseMetaGoImports(r io.Reader) (imports []metaImport) {
 			})
 		}
 	}
-	return
 }
 
 // attrValue returns the attribute value for the case-insensitive key

src/cmd/yacc/yacc.go

@@ -3164,7 +3164,6 @@ func ungetrune(f *bufio.Reader, c rune) {
 
 func write(f *bufio.Writer, b []byte, n int) int {
 	panic("write")
-	return 0
 }
 
 func open(s string) *bufio.Reader {

src/pkg/compress/flate/inflate.go

@@ -640,7 +640,6 @@ func (f *decompressor) huffSym(h *huffmanDecoder) (int, error) {
 			return int(chunk >> huffmanValueShift), nil
 		}
 	}
-	return 0, CorruptInputError(f.roffset)
 }
 
 // Flush any buffered output to the underlying writer.

src/pkg/compress/gzip/gunzip.go

@@ -120,7 +120,6 @@ func (z *Reader) readString() (string, error) {
 			return string(z.buf[0:i]), nil
 		}
 	}
-	panic("not reached")
 }
 
 func (z *Reader) read2() (uint32, error) {

src/pkg/compress/lzw/reader.go

@@ -202,7 +202,6 @@ func (d *decoder) decode() {
 			return
 		}
 	}
-	panic("unreachable")
 }
 
 func (d *decoder) flush() {

src/pkg/crypto/dsa/dsa_test.go

@@ -63,8 +63,9 @@ func testParameterGeneration(t *testing.T, sizes ParameterSizes, L, N int) {
 }
 
 func TestParameterGeneration(t *testing.T) {
-	// This test is too slow to run all the time.
-	return
+	if testing.Short() {
+		t.Skip("skipping parameter generation test in short mode")
+	}
 
 	testParameterGeneration(t, L1024N160, 1024, 160)
 	testParameterGeneration(t, L2048N224, 2048, 224)

src/pkg/crypto/rand/util.go

@@ -98,8 +98,6 @@ func Prime(rand io.Reader, bits int) (p *big.Int, err error) {
 			return
 		}
 	}
-
-	return
 }
 
 // Int returns a uniform random value in [0, max).
@@ -130,6 +128,4 @@ func Int(rand io.Reader, max *big.Int) (n *big.Int, err error) {
 			return
 		}
 	}
-
-	return
 }

src/pkg/encoding/asn1/marshal.go

@@ -460,7 +460,6 @@ func marshalBody(out *forkableWriter, value reflect.Value, params fieldParameter
 		default:
 			return marshalUTF8String(out, v.String())
 		}
-		return
 	}
 
 	return StructuralError{"unknown Go type"}

src/pkg/encoding/csv/reader.go

@@ -212,7 +212,6 @@ func (r *Reader) skip(delim rune) error {
 			return nil
 		}
 	}
-	panic("unreachable")
 }
 
 // parseRecord reads and parses a single csv record from r.
@@ -249,7 +248,6 @@ func (r *Reader) parseRecord() (fields []string, err error) {
 			return nil, err
 		}
 	}
-	panic("unreachable")
 }
 
 // parseField parses the next field in the record.  The read field is

src/pkg/encoding/gob/decode.go

@@ -1066,7 +1066,6 @@ func (dec *Decoder) compatibleType(fr reflect.Type, fw typeId, inProgress map[re
 	case reflect.Struct:
 		return true
 	}
-	return true
 }
 
 // typeString returns a human-readable description of the type identified by remoteId.

src/pkg/encoding/gob/type.go

@@ -526,7 +526,6 @@ func newTypeObject(name string, ut *userTypeInfo, rt reflect.Type) (gobType, err
 	default:
 		return nil, errors.New("gob NewTypeObject can't handle type: " + rt.String())
 	}
-	return nil, nil
 }
 
 // isExported reports whether this is an exported - upper case - name.

src/pkg/encoding/json/decode.go

@@ -868,7 +868,6 @@ func (d *decodeState) literalInterface() interface{} {
 		}
 		return n
 	}
-	panic("unreachable")
 }
 
 // getu4 decodes \uXXXX from the beginning of s, returning the hex value,

src/pkg/html/template/transition.go

@@ -429,7 +429,6 @@ func tCSS(c context, s []byte) (context, int) {
 		}
 		k = i + 1
 	}
-	panic("unreachable")
 }
 
 // tCSSStr is the context transition function for the CSS string and URL states.
@@ -470,7 +469,6 @@ func tCSSStr(c context, s []byte) (context, int) {
 		c, _ = tURL(c, decodeCSS(s[:i+1]))
 		k = i + 1
 	}
-	panic("unreachable")
 }
 
 // tError is the context transition function for the error state.

src/pkg/math/big/nat.go

@@ -1021,8 +1021,6 @@ func trailingZeroBits(x Word) uint {
 	default:
 		panic("unknown word size")
 	}
-
-	return 0
 }
 
 // trailingZeroBits returns the number of consecutive least significant zero

src/pkg/net/http/httputil/reverseproxy.go

@@ -202,7 +202,6 @@ func (m *maxLatencyWriter) flushLoop() {
 			m.lk.Unlock()
 		}
 	}
-	panic("unreached")
 }
 
 func (m *maxLatencyWriter) stop() { m.done <- true }

src/pkg/net/ip.go

@@ -222,7 +222,6 @@ func (ip IP) DefaultMask() IPMask {
 	default:
 		return classCMask
 	}
-	return nil // not reached
 }
 
 func allFF(b []byte) bool {

src/pkg/net/unixsock_posix.go

@@ -99,7 +99,6 @@ func sotypeToNet(sotype int) string {
 	default:
 		panic("sotypeToNet unknown socket type")
 	}
-	return ""
 }
 
 // UnixConn is an implementation of the Conn interface for connections

src/pkg/os/file_posix.go

@@ -46,8 +46,6 @@ func Readlink(name string) (string, error) {
 			return string(b[0:n]), nil
 		}
 	}
-	// Silence 6g.
-	return "", nil
 }
 
 // Rename renames a file.

src/pkg/os/getwd.go

@@ -90,8 +90,6 @@ func Getwd() (pwd string, err error) {
 				}
 			}
 		}
-		fd.Close()
-		return "", ErrNotExist
 
 	Found:
 		pd, err := fd.Stat()

src/pkg/reflect/tostring_test.go

@@ -92,5 +92,4 @@ func valueToString(val Value) string {
 	default:
 		panic("valueToString: can't print type " + typ.String())
 	}
-	return "valueToString: can't happen"
 }

src/pkg/strconv/extfloat.go

@@ -636,7 +636,6 @@ func (f *extFloat) ShortestDecimal(d *decimalSlice, lower, upper *extFloat) bool
 				1<<shift, multiplier*2)
 		}
 	}
-	return false
 }
 
 // adjustLastDigit modifies d = x-currentDiff*ε, to get closest to

src/pkg/syscall/exec_bsd.go

@@ -215,11 +215,6 @@ childerror:
 	for {
 		RawSyscall(SYS_EXIT, 253, 0, 0)
 	}
-
-	// Calling panic is not actually safe,
-	// but the for loop above won't break
-	// and this shuts up the compiler.
-	panic("unreached")
 }
 
 // Try to open a pipe with O_CLOEXEC set on both file descriptors.

src/pkg/testing/quick/quick.go

@@ -140,8 +140,6 @@ func Value(t reflect.Type, rand *rand.Rand) (value reflect.Value, ok bool) {
 	default:
 		return reflect.Value{}, false
 	}
-
-	return
 }
 
 // A Config structure contains options for running a test.

src/pkg/text/template/parse/parse.go

@@ -429,7 +429,6 @@ func (t *Tree) pipeline(context string) (pipe *PipeNode) {
 			t.unexpected(token, context)
 		}
 	}
-	return
 }
 
 func (t *Tree) parseControl(context string) (pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) {