go/constants: rename go/exact to go/constants

since the "precision" parameter means constant arithmetic is not
necessarily exact.

As requested by gri, within go/types, the local import name 'exact'
has been kept, to reduce the diff with the x/tools branch.  This may
be changed later.

Since the go/types.bash script was already obsolete, I added a comment
to this effect.

Tested with all.bash.

Change-Id: I45153688d9d8afa8384fb15229b0124c686059b4
Reviewed-on: https://go-review.googlesource.com/9242Reviewed-by: Rob Pike <r@golang.org>

src/go/build/deps_test.go

@@ -340,11 +340,11 @@ var pkgDeps = map[string][]string{
 	// dependencies.  Do not simply update them in situ.
 	"container/heap":           {"sort"},
 	"debug/plan9obj":           {"encoding/binary", "errors", "fmt", "io", "os"},
-	"go/exact":                 {"fmt", "go/token", "math/big", "strconv"},
+	"go/constants":             {"fmt", "go/token", "math/big", "strconv"},
 	"go/format":                {"bytes", "fmt", "go/ast", "go/parser", "go/printer", "go/token", "internal/format", "io"},
 	"go/importer":              {"go/internal/gcimporter", "go/types", "io", "runtime"},
-	"go/internal/gcimporter":   {"bufio", "errors", "fmt", "go/build", "go/exact", "go/token", "go/types", "io", "os", "path/filepath", "strconv", "strings", "text/scanner"},
-	"go/types":                 {"bytes", "container/heap", "fmt", "go/ast", "go/exact", "go/parser", "go/token", "io", "math", "path", "sort", "strconv", "strings", "sync", "unicode"},
+	"go/internal/gcimporter":   {"bufio", "errors", "fmt", "go/build", "go/constants", "go/token", "go/types", "io", "os", "path/filepath", "strconv", "strings", "text/scanner"},
+	"go/types":                 {"bytes", "container/heap", "fmt", "go/ast", "go/constants", "go/parser", "go/token", "io", "math", "path", "sort", "strconv", "strings", "sync", "unicode"},
 	"image/internal/imageutil": {"image"},
 	"internal/format":          {"bytes", "go/ast", "go/parser", "go/printer", "go/token", "strings"},
 	"internal/mime":            {"bytes", "encoding/base64", "errors", "fmt", "io", "io/ioutil", "strconv", "strings", "unicode"},

src/go/exact/go13.go → src/go/constants/go13.go

@@ -4,7 +4,7 @@
 
 // +build !go1.4
 
-package exact
+package constants
 
 import (
 	"math"

src/go/exact/go14.go → src/go/constants/go14.go

@@ -4,7 +4,7 @@
 
 // +build go1.4
 
-package exact
+package constants
 
 import "math/big"
 

src/go/exact/exact.go → src/go/constants/value.go

@@ -2,16 +2,16 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package exact implements Values representing untyped
+// Package constants implements Values representing untyped
 // Go constants and the corresponding operations. Values
-// and operations have unlimited precision.
+// and operations may have arbitrary or unlimited precision.
 //
 // A special Unknown value may be used when a value
 // is unknown due to an error. Operations on unknown
 // values produce unknown values unless specified
 // otherwise.
 //
-package exact // import "go/exact"
+package constants // import "go/constants"
 
 import (
 	"fmt"

src/go/exact/exact_test.go → src/go/constants/value_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package exact
+package constants
 
 import (
 	"go/token"

src/go/internal/gcimporter/gcimporter.go

@@ -18,7 +18,7 @@ import (
 	"strings"
 	"text/scanner"
 
-	"go/exact"
+	exact "go/constants"
 	"go/types"
 )
 

src/go/types.bash

@@ -9,6 +9,10 @@
 # original sources in x/tools. Imports are renamed as needed.
 #
 # Delete this script once go/exact and go/types don't exist anymore in x/tools.
+#
+# NOTE(adonovan): the standard packages have intentionally diverged
+# from x/tools, so this script is a unlikely to be useful.  Upstream
+# changes should be cherry-picked in to the standard library.
 
 set -e
 

src/go/types/api.go

@@ -28,7 +28,7 @@ import (
 	"bytes"
 	"fmt"
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 )
 

src/go/types/builtins.go

@@ -8,7 +8,7 @@ package types
 
 import (
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 )
 

src/go/types/check.go

@@ -8,7 +8,7 @@ package types
 
 import (
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 )
 

src/go/types/conversions.go

@@ -6,7 +6,7 @@
 
 package types
 
-import "go/exact"
+import exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 
 // Conversion type-checks the conversion T(x).
 // The result is in x.

src/go/types/decl.go

@@ -6,7 +6,7 @@ package types
 
 import (
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 )
 

src/go/types/expr.go

@@ -9,7 +9,7 @@ package types
 import (
 	"fmt"
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 	"math"
 )

src/go/types/object.go

@@ -8,7 +8,7 @@ import (
 	"bytes"
 	"fmt"
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 )
 

src/go/types/operand.go

@@ -9,7 +9,7 @@ package types
 import (
 	"bytes"
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 )
 

src/go/types/resolver.go

@@ -7,7 +7,7 @@ package types
 import (
 	"fmt"
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 	pathLib "path"
 	"strconv"

src/go/types/self_test.go

@@ -31,7 +31,7 @@ func TestSelf(t *testing.T) {
 	conf := Config{Importer: importer.Default()}
 	_, err = conf.Check("go/types", fset, files, nil)
 	if err != nil {
-		// Importing go.tools/go/exact doensn't work in the
+		// Importing go/constants doesn't work in the
 		// build dashboard environment. Don't report an error
 		// for now so that the build remains green.
 		// TODO(gri) fix this

src/go/types/stmt.go

@@ -9,7 +9,7 @@ package types
 import (
 	"fmt"
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 )
 

src/go/types/typexpr.go

@@ -8,7 +8,7 @@ package types
 
 import (
 	"go/ast"
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 	"sort"
 	"strconv"

src/go/types/universe.go

@@ -7,7 +7,7 @@
 package types
 
 import (
-	"go/exact"
+	exact "go/constants" // Renamed to reduce diffs from x/tools.  TODO: remove
 	"go/token"
 	"strings"
 )