5 files changed, 56 insertions, 10 deletions
diff --git a/src/cmd/go.mod b/src/cmd/go.mod
index db43541d89..407f12b3e0 100644
--- a/src/cmd/go.mod
+++ b/src/cmd/go.mod
@@ -8,5 +8,5 @@ require (
 	golang.org/x/arch v0.0.0-20181203225421-5a4828bb7045
 	golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c
 	golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82 // indirect
-	golang.org/x/tools v0.0.0-20190510144052-35884eef200b
+	golang.org/x/tools v0.0.0-20190514135123-4789ca9922f0
 )
diff --git a/src/cmd/go.sum b/src/cmd/go.sum
index f6a34ea1f0..92886bba7b 100644
--- a/src/cmd/go.sum
+++ b/src/cmd/go.sum
@@ -17,3 +17,7 @@ golang.org/x/tools v0.0.0-20190509153222-73554e0f7805 h1:1ufBXAsTpUhSmmPXEEs5PrG
 golang.org/x/tools v0.0.0-20190509153222-73554e0f7805/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 golang.org/x/tools v0.0.0-20190510144052-35884eef200b h1:4muk7BhMes67ZgDeK3n4Jvi+FvNDRZzh6ZRqIXZNYwQ=
 golang.org/x/tools v0.0.0-20190510144052-35884eef200b/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
+golang.org/x/tools v0.0.0-20190513233021-7d589f28aaf4 h1:sIGsLZaMtLBc5sLK7s2xtr7VaKk8h31mrJyHwEZq2WQ=
+golang.org/x/tools v0.0.0-20190513233021-7d589f28aaf4/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
+golang.org/x/tools v0.0.0-20190514135123-4789ca9922f0 h1:0Bz67IMuNMofIoO/F+rX8oPltlfrAC5HU68DEyynMQg=
+golang.org/x/tools v0.0.0-20190514135123-4789ca9922f0/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go
index a03a185fc0..062d062487 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go
@@ -8,6 +8,7 @@ package analysisflags
 
 import (
 	"crypto/sha256"
+	"encoding/gob"
 	"encoding/json"
 	"flag"
 	"fmt"
@@ -32,6 +33,14 @@ var (
 // including (in multi mode) a flag named after the analyzer,
 // parses the flags, then filters and returns the list of
 // analyzers enabled by flags.
+//
+// The result is intended to be passed to unitchecker.Run or checker.Run.
+// Use in unitchecker.Run will gob.Register all fact types for the returned
+// graph of analyzers but of course not the ones only reachable from
+// dropped analyzers. To avoid inconsistency about which gob types are
+// registered from run to run, Parse itself gob.Registers all the facts
+// only reachable from dropped analyzers.
+// This is not a particularly elegant API, but this is an internal package.
 func Parse(analyzers []*analysis.Analyzer, multi bool) []*analysis.Analyzer {
 	// Connect each analysis flag to the command line as -analysis.flag.
 	enabled := make(map[*analysis.Analyzer]*triState)
@@ -88,6 +97,8 @@ func Parse(analyzers []*analysis.Analyzer, multi bool) []*analysis.Analyzer {
 		os.Exit(0)
 	}
 
+	everything := expand(analyzers)
+
 	// If any -NAME flag is true,  run only those analyzers. Otherwise,
 	// if any -NAME flag is false, run all but those analyzers.
 	if multi {
@@ -119,9 +130,35 @@ func Parse(analyzers []*analysis.Analyzer, multi bool) []*analysis.Analyzer {
 		}
 	}
 
+	// Register fact types of skipped analyzers
+	// in case we encounter them in imported files.
+	kept := expand(analyzers)
+	for a := range everything {
+		if !kept[a] {
+			for _, f := range a.FactTypes {
+				gob.Register(f)
+			}
+		}
+	}
+
 	return analyzers
 }
 
+func expand(analyzers []*analysis.Analyzer) map[*analysis.Analyzer]bool {
+	seen := make(map[*analysis.Analyzer]bool)
+	var visitAll func([]*analysis.Analyzer)
+	visitAll = func(analyzers []*analysis.Analyzer) {
+		for _, a := range analyzers {
+			if !seen[a] {
+				seen[a] = true
+				visitAll(a.Requires)
+			}
+		}
+	}
+	visitAll(analyzers)
+	return seen
+}
+
 func printFlags() {
 	type jsonFlag struct {
 		Name  string
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go
index 833c9d7aae..c82d3675b9 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go
@@ -30,8 +30,13 @@ func run(pass *analysis.Pass) (interface{}, error) {
 	nodeFilter := []ast.Node{
 		(*ast.BinaryExpr)(nil),
 	}
+	seen := make(map[*ast.BinaryExpr]bool)
 	inspect.Preorder(nodeFilter, func(n ast.Node) {
 		e := n.(*ast.BinaryExpr)
+		if seen[e] {
+			// Already processed as a subexpression of an earlier node.
+			return
+		}
 
 		var op boolOp
 		switch e.Op {
@@ -43,10 +48,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 			return
 		}
 
-		// TODO(adonovan): this reports n(n-1)/2 errors for an
-		// expression e||...||e of depth n. Fix.
-		// See https://golang.org/issue/28086.
-		comm := op.commutativeSets(pass.TypesInfo, e)
+		comm := op.commutativeSets(pass.TypesInfo, e, seen)
 		for _, exprs := range comm {
 			op.checkRedundant(pass, exprs)
 			op.checkSuspect(pass, exprs)
@@ -70,8 +72,9 @@ var (
 // expressions in e that are connected by op.
 // For example, given 'a || b || f() || c || d' with the or op,
 // commutativeSets returns {{b, a}, {d, c}}.
-func (op boolOp) commutativeSets(info *types.Info, e *ast.BinaryExpr) [][]ast.Expr {
-	exprs := op.split(e)
+// commutativeSets adds any expanded BinaryExprs to seen.
+func (op boolOp) commutativeSets(info *types.Info, e *ast.BinaryExpr, seen map[*ast.BinaryExpr]bool) [][]ast.Expr {
+	exprs := op.split(e, seen)
 
 	// Partition the slice of expressions into commutative sets.
 	i := 0
@@ -188,11 +191,13 @@ func hasSideEffects(info *types.Info, e ast.Expr) bool {
 // split returns a slice of all subexpressions in e that are connected by op.
 // For example, given 'a || (b || c) || d' with the or op,
 // split returns []{d, c, b, a}.
-func (op boolOp) split(e ast.Expr) (exprs []ast.Expr) {
+// seen[e] is already true; any newly processed exprs are added to seen.
+func (op boolOp) split(e ast.Expr, seen map[*ast.BinaryExpr]bool) (exprs []ast.Expr) {
 	for {
 		e = unparen(e)
 		if b, ok := e.(*ast.BinaryExpr); ok && b.Op == op.tok {
-			exprs = append(exprs, op.split(b.Y)...)
+			seen[b] = true
+			exprs = append(exprs, op.split(b.Y, seen)...)
 			e = b.X
 		} else {
 			exprs = append(exprs, e)
diff --git a/src/cmd/vendor/modules.txt b/src/cmd/vendor/modules.txt
index 53cf548512..ef8408cd51 100644
--- a/src/cmd/vendor/modules.txt
+++ b/src/cmd/vendor/modules.txt
@@ -26,7 +26,7 @@ golang.org/x/crypto/ssh/terminal
 # golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82
 golang.org/x/sys/unix
 golang.org/x/sys/windows
-# golang.org/x/tools v0.0.0-20190510144052-35884eef200b
+# golang.org/x/tools v0.0.0-20190514135123-4789ca9922f0
 golang.org/x/tools/go/analysis
 golang.org/x/tools/go/analysis/internal/analysisflags
 golang.org/x/tools/go/analysis/internal/facts