go/doc: don't lose exported consts/vars with unexported type

Fixes #2998.

R=rsc
CC=golang-dev
https://golang.org/cl/5650078

src/pkg/go/doc/reader.go

@@ -274,7 +274,7 @@ func (r *reader) readValue(decl *ast.GenDecl) {
 	// determine values list with which to associate the Value for this decl
 	values := &r.values
 	const threshold = 0.75
-	if domName != "" && domFreq >= int(float64(len(decl.Specs))*threshold) {
+	if domName != "" && r.isVisible(domName) && domFreq >= int(float64(len(decl.Specs))*threshold) {
 		// typed entries are sufficiently frequent
 		if typ := r.lookupType(domName); typ != nil {
 			values = &typ.values // associate with that type

src/pkg/go/doc/testdata/b.0.golden

@@ -11,19 +11,47 @@ FILENAMES
 	testdata/b.go
 
 CONSTANTS
+	// 
+	const (
+		C1	notExported	= iota
+		C2
+	
+		C4
+		C5
+	)
+
+	// 
+	const C notExported = 0
+
 	// 
 	const Pi = 3.14	// Pi
 
 
 VARIABLES
+	// 
+	var (
+		U1, U2, U4, U5	notExported
+	
+		U7	notExported	= 7
+	)
+
 	// 
 	var MaxInt int	// MaxInt
 
+	// 
+	var V notExported
+
+	// 
+	var V1, V2, V4, V5 notExported
+
 
 FUNCTIONS
 	// 
 	func F(x int) int
 
+	// 
+	func F1() notExported
+
 	// Always under the package functions list. 
 	func NotAFactory() int
 

src/pkg/go/doc/testdata/b.1.golden

@@ -38,8 +38,42 @@ TYPES
 	// 
 	func (x *T) M()
 
+	// 
+	type notExported int
+
+	// 
+	const (
+		C1	notExported	= iota
+		C2
+		c3
+		C4
+		C5
+	)
+
+	// 
+	const C notExported = 0
+
+	// 
+	var (
+		U1, U2, u3, U4, U5	notExported
+		u6			notExported
+		U7			notExported	= 7
+	)
+
+	// 
+	var V notExported
+
+	// 
+	var V1, V2, v3, V4, V5 notExported
+
+	// 
+	func F1() notExported
+
+	// 
+	func f2() notExported
+
 	// Should only appear if AllDecls is set. 
-	type uint struct{}
+	type uint struct{}	// overrides a predeclared type uint
 
 	// Associated with uint type if AllDecls is set. 
 	func UintFactory() uint

src/pkg/go/doc/testdata/b.2.golden

@@ -11,19 +11,47 @@ FILENAMES
 	testdata/b.go
 
 CONSTANTS
+	// 
+	const (
+		C1	notExported	= iota
+		C2
+	
+		C4
+		C5
+	)
+
+	// 
+	const C notExported = 0
+
 	// 
 	const Pi = 3.14	// Pi
 
 
 VARIABLES
+	// 
+	var (
+		U1, U2, U4, U5	notExported
+	
+		U7	notExported	= 7
+	)
+
 	// 
 	var MaxInt int	// MaxInt
 
+	// 
+	var V notExported
+
+	// 
+	var V1, V2, V4, V5 notExported
+
 
 FUNCTIONS
 	// 
 	func F(x int) int
 
+	// 
+	func F1() notExported
+
 	// Always under the package functions list. 
 	func NotAFactory() int
 

src/pkg/go/doc/testdata/b.go

@@ -6,6 +6,7 @@ package b
 
 import "a"
 
+// ----------------------------------------------------------------------------
 // Basic declarations
 
 const Pi = 3.14   // Pi
@@ -28,3 +29,30 @@ func uintFactory() uint {}
 
 // Should only appear if AllDecls is set.
 type uint struct{} // overrides a predeclared type uint
+
+// ----------------------------------------------------------------------------
+// Exported declarations associated with non-exported types must always be shown.
+
+type notExported int
+
+const C notExported = 0
+
+const (
+	C1 notExported = iota
+	C2
+	c3
+	C4
+	C5
+)
+
+var V notExported
+var V1, V2, v3, V4, V5 notExported
+
+var (
+	U1, U2, u3, U4, U5 notExported
+	u6                 notExported
+	U7                 notExported = 7
+)
+
+func F1() notExported {}
+func f2() notExported {}