libgo: update to Go 1.13beta1 release

    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/193497

From-SVN: r275473

21 files changed, 383 insertions, 138 deletions

diff --git a/libgo/go/golang.org/x/tools/go/analysis/analysis.go b/libgo/go/golang.org/x/tools/go/analysis/analysis.go
index 21baa02a8de..19e1e421a38 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/analysis.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/analysis.go
@@ -87,6 +87,7 @@ type Pass struct {
 	OtherFiles []string       // names of non-Go files of this package
 	Pkg        *types.Package // type information about the package
 	TypesInfo  *types.Info    // type information about the syntax trees
+	TypesSizes types.Sizes    // function for computing sizes of types
 
 	// Report reports a Diagnostic, a finding about a specific location
 	// in the analyzed source code such as a potential mistake.
@@ -127,10 +128,32 @@ type Pass struct {
 	// See comments for ExportObjectFact.
 	ExportPackageFact func(fact Fact)
 
+	// AllPackageFacts returns a new slice containing all package facts in unspecified order.
+	// WARNING: This is an experimental API and may change in the future.
+	AllPackageFacts func() []PackageFact
+
+	// AllObjectFacts returns a new slice containing all object facts in unspecified order.
+	// WARNING: This is an experimental API and may change in the future.
+	AllObjectFacts func() []ObjectFact
+
 	/* Further fields may be added in future. */
 	// For example, suggested or applied refactorings.
 }
 
+// PackageFact is a package together with an associated fact.
+// WARNING: This is an experimental API and may change in the future.
+type PackageFact struct {
+	Package *types.Package
+	Fact    Fact
+}
+
+// ObjectFact is an object together with an associated fact.
+// WARNING: This is an experimental API and may change in the future.
+type ObjectFact struct {
+	Object types.Object
+	Fact   Fact
+}
+
 // Reportf is a helper function that reports a Diagnostic using the
 // specified position and formatted error message.
 func (pass *Pass) Reportf(pos token.Pos, format string, args ...interface{}) {
@@ -138,6 +161,15 @@ func (pass *Pass) Reportf(pos token.Pos, format string, args ...interface{}) {
 	pass.Report(Diagnostic{Pos: pos, Message: msg})
 }
 
+// reportNodef is a helper function that reports a Diagnostic using the
+// range denoted by the AST node.
+//
+// WARNING: This is an experimental API and may change in the future.
+func (pass *Pass) reportNodef(node ast.Node, format string, args ...interface{}) {
+	msg := fmt.Sprintf(format, args...)
+	pass.Report(Diagnostic{Pos: node.Pos(), End: node.End(), Message: msg})
+}
+
 func (pass *Pass) String() string {
 	return fmt.Sprintf("%s@%s", pass.Analyzer.Name, pass.Pkg.Path())
 }
@@ -180,13 +212,17 @@ type Fact interface {
 	AFact() // dummy method to avoid type errors
 }
 
-// A Diagnostic is a message associated with a source location.
+// A Diagnostic is a message associated with a source location or range.
 //
 // An Analyzer may return a variety of diagnostics; the optional Category,
 // which should be a constant, may be used to classify them.
 // It is primarily intended to make it easy to look up documentation.
+//
+// If End is provided, the diagnostic is specified to apply to the range between
+// Pos and End.
 type Diagnostic struct {
 	Pos      token.Pos
-	Category string // optional
+	End      token.Pos // optional
+	Category string    // optional
 	Message  string
 }
diff --git a/libgo/go/golang.org/x/tools/go/analysis/doc.go b/libgo/go/golang.org/x/tools/go/analysis/doc.go
index f925849ab50..2d44b0458a9 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/doc.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/doc.go
@@ -246,7 +246,7 @@ An Analyzer that uses facts must declare their types:
 
 	var Analyzer = &analysis.Analyzer{
 		Name:       "printf",
-		FactTypes: []reflect.Type{reflect.TypeOf(new(isWrapper))},
+		FactTypes: []analysis.Fact{new(isWrapper)},
 		...
 	}
 
diff --git a/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go b/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go
index 729ac3b4176..a3c2f096300 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go
+++ b/libgo/go/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
@@ -152,12 +189,13 @@ func printFlags() {
 // addVersionFlag registers a -V flag that, if set,
 // prints the executable version and exits 0.
 //
-// It is a variable not a function to permit easy
-// overriding in the copy vendored in $GOROOT/src/cmd/vet:
-//
-// func init() { addVersionFlag = objabi.AddVersionFlag }
-var addVersionFlag = func() {
-	flag.Var(versionFlag{}, "V", "print version and exit")
+// If the -V flag already exists — for example, because it was already
+// registered by a call to cmd/internal/objabi.AddVersionFlag — then
+// addVersionFlag does nothing.
+func addVersionFlag() {
+	if flag.Lookup("V") == nil {
+		flag.Var(versionFlag{}, "V", "print version and exit")
+	}
 }
 
 // versionFlag minimally complies with the -V protocol required by "go vet".
@@ -285,9 +323,14 @@ func PrintPlain(fset *token.FileSet, diag analysis.Diagnostic) {
 
 	// -c=N: show offending line plus N lines of context.
 	if Context >= 0 {
+		posn := fset.Position(diag.Pos)
+		end := fset.Position(diag.End)
+		if !end.IsValid() {
+			end = posn
+		}
 		data, _ := ioutil.ReadFile(posn.Filename)
 		lines := strings.Split(string(data), "\n")
-		for i := posn.Line - Context; i <= posn.Line+Context; i++ {
+		for i := posn.Line - Context; i <= end.Line+Context; i++ {
 			if 1 <= i && i <= len(lines) {
 				fmt.Fprintf(os.Stderr, "%d\t%s\n", i, lines[i-1])
 			}
@@ -315,6 +358,8 @@ func (tree JSONTree) Add(fset *token.FileSet, id, name string, diags []analysis.
 			Message  string `json:"message"`
 		}
 		var diagnostics []jsonDiagnostic
+		// TODO(matloob): Should the JSON diagnostics contain ranges?
+		// If so, how should they be formatted?
 		for _, f := range diags {
 			diagnostics = append(diagnostics, jsonDiagnostic{
 				Category: f.Category,
diff --git a/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/help.go b/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
index 043b97896dd..c5a70f3b7d6 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
@@ -4,6 +4,7 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"os"
 	"sort"
 	"strings"
 
@@ -47,6 +48,7 @@ func Help(progname string, analyzers []*analysis.Analyzer, args []string) {
 				fs.Var(f.Value, f.Name, f.Usage)
 			}
 		})
+		fs.SetOutput(os.Stdout)
 		fs.PrintDefaults()
 
 		fmt.Printf("\nTo see details and flags of a specific analyzer, run '%s help name'.\n", progname)
@@ -75,6 +77,7 @@ outer:
 					}
 					fs.Var(f.Value, a.Name+"."+f.Name, f.Usage)
 				})
+				fs.SetOutput(os.Stdout)
 				fs.PrintDefaults()
 
 				if len(paras) > 1 {
diff --git a/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/patch.go b/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/patch.go
deleted file mode 100644
index 8f9741055cb..00000000000
--- a/libgo/go/golang.org/x/tools/go/analysis/internal/analysisflags/patch.go
+++ /dev/null
@@ -1,7 +0,0 @@
-package analysisflags
-
-import "cmd/internal/objabi"
-
-// This additional file changes the behavior of the vendored code.
-
-func init() { addVersionFlag = objabi.AddVersionFlag }
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go b/libgo/go/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go
index dce1ef7bd5e..d41c4e97e32 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go
@@ -114,7 +114,8 @@ func init() {
 			// library we cannot assume types.SizesFor is consistent with arches.
 			// For now, assume 64-bit norms and print a warning.
 			// But this warning should really be deferred until we attempt to use
-			// arch, which is very unlikely.
+			// arch, which is very unlikely. Better would be
+			// to defer size computation until we have Pass.TypesSizes.
 			arch.sizes = types.SizesFor("gc", "amd64")
 			log.Printf("unknown architecture %s", arch.name)
 		}
@@ -129,7 +130,7 @@ var (
 	asmPlusBuild = re(`//\s+\+build\s+([^\n]+)`)
 	asmTEXT      = re(`\bTEXT\b(.*)·([^\(]+)\(SB\)(?:\s*,\s*([0-9A-Z|+()]+))?(?:\s*,\s*\$(-?[0-9]+)(?:-([0-9]+))?)?`)
 	asmDATA      = re(`\b(DATA|GLOBL)\b`)
-	asmNamedFP   = re(`([a-zA-Z0-9_\xFF-\x{10FFFF}]+)(?:\+([0-9]+))\(FP\)`)
+	asmNamedFP   = re(`\$?([a-zA-Z0-9_\xFF-\x{10FFFF}]+)(?:\+([0-9]+))\(FP\)`)
 	asmUnnamedFP = re(`[^+\-0-9](([0-9]+)\(FP\))`)
 	asmSP        = re(`[^+\-0-9](([0-9]+)\(([A-Z0-9]+)\))`)
 	asmOpcode    = re(`^\s*(?:[A-Z0-9a-z_]+:)?\s*([A-Z]+)\s*([^,]*)(?:,\s*(.*))?`)
@@ -183,6 +184,7 @@ Files:
 			fnName             string
 			localSize, argSize int
 			wroteSP            bool
+			noframe            bool
 			haveRetArg         bool
 			retLine            []int
 		)
@@ -230,6 +232,11 @@ Files:
 				}
 			}
 
+			// Ignore comments and commented-out code.
+			if i := strings.Index(line, "//"); i >= 0 {
+				line = line[:i]
+			}
+
 			if m := asmTEXT.FindStringSubmatch(line); m != nil {
 				flushRet()
 				if arch == "" {
@@ -253,7 +260,7 @@ Files:
 					// identifiers to represent the directory separator.
 					pkgPath = strings.Replace(pkgPath, "∕", "/", -1)
 					if pkgPath != pass.Pkg.Path() {
-						log.Printf("%s:%d: [%s] cannot check cross-package assembly function: %s is in package %s", fname, lineno, arch, fnName, pkgPath)
+						// log.Printf("%s:%d: [%s] cannot check cross-package assembly function: %s is in package %s", fname, lineno, arch, fnName, pkgPath)
 						fn = nil
 						fnName = ""
 						continue
@@ -274,7 +281,8 @@ Files:
 					localSize += archDef.intSize
 				}
 				argSize, _ = strconv.Atoi(m[5])
-				if fn == nil && !strings.Contains(fnName, "<>") {
+				noframe = strings.Contains(flag, "NOFRAME")
+				if fn == nil && !strings.Contains(fnName, "<>") && !noframe {
 					badf("function %s missing Go declaration", fnName)
 				}
 				wroteSP = false
@@ -304,13 +312,18 @@ Files:
 				continue
 			}
 
-			if strings.Contains(line, ", "+archDef.stack) || strings.Contains(line, ",\t"+archDef.stack) {
+			if strings.Contains(line, ", "+archDef.stack) || strings.Contains(line, ",\t"+archDef.stack) || strings.Contains(line, "NOP "+archDef.stack) || strings.Contains(line, "NOP\t"+archDef.stack) {
 				wroteSP = true
 				continue
 			}
 
+			if arch == "wasm" && strings.Contains(line, "CallImport") {
+				// CallImport is a call out to magic that can write the result.
+				haveRetArg = true
+			}
+
 			for _, m := range asmSP.FindAllStringSubmatch(line, -1) {
-				if m[3] != archDef.stack || wroteSP {
+				if m[3] != archDef.stack || wroteSP || noframe {
 					continue
 				}
 				off := 0
@@ -370,7 +383,7 @@ Files:
 					}
 					continue
 				}
-				asmCheckVar(badf, fn, line, m[0], off, v)
+				asmCheckVar(badf, fn, line, m[0], off, v, archDef)
 			}
 		}
 		flushRet()
@@ -588,7 +601,7 @@ func asmParseDecl(pass *analysis.Pass, decl *ast.FuncDecl) map[string]*asmFunc {
 }
 
 // asmCheckVar checks a single variable reference.
-func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr string, off int, v *asmVar) {
+func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr string, off int, v *asmVar, archDef *asmArch) {
 	m := asmOpcode.FindStringSubmatch(line)
 	if m == nil {
 		if !strings.HasPrefix(strings.TrimSpace(line), "//") {
@@ -597,6 +610,8 @@ func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr stri
 		return
 	}
 
+	addr := strings.HasPrefix(expr, "$")
+
 	// Determine operand sizes from instruction.
 	// Typically the suffix suffices, but there are exceptions.
 	var src, dst, kind asmKind
@@ -616,10 +631,13 @@ func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr stri
 	// They just take the address of it.
 	case "386.LEAL":
 		dst = 4
+		addr = true
 	case "amd64.LEAQ":
 		dst = 8
+		addr = true
 	case "amd64p32.LEAL":
 		dst = 4
+		addr = true
 	default:
 		switch fn.arch.name {
 		case "386", "amd64":
@@ -724,6 +742,11 @@ func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr stri
 		vs = v.inner[0].size
 		vt = v.inner[0].typ
 	}
+	if addr {
+		vk = asmKind(archDef.ptrSize)
+		vs = archDef.ptrSize
+		vt = "address"
+	}
 
 	if off != v.off {
 		var inner bytes.Buffer
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/bools/bools.go b/libgo/go/golang.org/x/tools/go/analysis/passes/bools/bools.go
index 833c9d7aae1..c82d3675b95 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/bools/bools.go
+++ b/libgo/go/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/libgo/go/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go b/libgo/go/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go
index a6e76a192de..42a690dbab6 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go
@@ -9,7 +9,6 @@ package cgocall
 import (
 	"fmt"
 	"go/ast"
-	"go/build"
 	"go/format"
 	"go/parser"
 	"go/token"
@@ -46,7 +45,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 		return nil, nil // doesn't use cgo
 	}
 
-	cgofiles, info, err := typeCheckCgoSourceFiles(pass.Fset, pass.Pkg, pass.Files, pass.TypesInfo)
+	cgofiles, info, err := typeCheckCgoSourceFiles(pass.Fset, pass.Pkg, pass.Files, pass.TypesInfo, pass.TypesSizes)
 	if err != nil {
 		return nil, err
 	}
@@ -172,7 +171,7 @@ func checkCgo(fset *token.FileSet, f *ast.File, info *types.Info, reportf func(t
 // limited ourselves here to preserving function bodies and initializer
 // expressions since that is all that the cgocall analyzer needs.
 //
-func typeCheckCgoSourceFiles(fset *token.FileSet, pkg *types.Package, files []*ast.File, info *types.Info) ([]*ast.File, *types.Info, error) {
+func typeCheckCgoSourceFiles(fset *token.FileSet, pkg *types.Package, files []*ast.File, info *types.Info, sizes types.Sizes) ([]*ast.File, *types.Info, error) {
 	const thispkg = "·this·"
 
 	// Which files are cgo files?
@@ -270,8 +269,7 @@ func typeCheckCgoSourceFiles(fset *token.FileSet, pkg *types.Package, files []*a
 		Importer: importerFunc(func(path string) (*types.Package, error) {
 			return importMap[path], nil
 		}),
-		// TODO(adonovan): Sizes should probably be provided by analysis.Pass.
-		Sizes: types.SizesFor("gccgo", build.Default.GOARCH),
+		Sizes: sizes,
 		Error: func(error) {}, // ignore errors (e.g. unused import)
 	}
 
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/composite/composite.go b/libgo/go/golang.org/x/tools/go/analysis/passes/composite/composite.go
index 9cca7781d00..2abe7c6d51e 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/composite/composite.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/composite/composite.go
@@ -21,7 +21,16 @@ const Doc = `check for unkeyed composite literals
 This analyzer reports a diagnostic for composite literals of struct
 types imported from another package that do not use the field-keyed
 syntax. Such literals are fragile because the addition of a new field
-(even if unexported) to the struct will cause compilation to fail.`
+(even if unexported) to the struct will cause compilation to fail.
+
+As an example,
+
+	err = &net.DNSConfigError{err}
+
+should be replaced by:
+
+	err = &net.DNSConfigError{Err: err}
+`
 
 var Analyzer = &analysis.Analyzer{
 	Name:             "composites",
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/errorsas/errorsas.go b/libgo/go/golang.org/x/tools/go/analysis/passes/errorsas/errorsas.go
new file mode 100644
index 00000000000..c411466c28e
--- /dev/null
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/errorsas/errorsas.go
@@ -0,0 +1,75 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The errorsas package defines an Analyzer that checks that the second arugment to
+// errors.As is a pointer to a type implementing error.
+package errorsas
+
+import (
+	"go/ast"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+)
+
+const doc = `report passing non-pointer or non-error values to errors.As
+
+The errorsas analysis reports calls to errors.As where the type
+of the second argument is not a pointer to a type implementing error.`
+
+var Analyzer = &analysis.Analyzer{
+	Name:     "errorsas",
+	Doc:      doc,
+	Requires: []*analysis.Analyzer{inspect.Analyzer},
+	Run:      run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+	switch pass.Pkg.Path() {
+	case "errors", "errors_test":
+		// These packages know how to use their own APIs.
+		// Sometimes they are testing what happens to incorrect programs.
+		return nil, nil
+	}
+
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+	nodeFilter := []ast.Node{
+		(*ast.CallExpr)(nil),
+	}
+	inspect.Preorder(nodeFilter, func(n ast.Node) {
+		call := n.(*ast.CallExpr)
+		fn := typeutil.StaticCallee(pass.TypesInfo, call)
+		if fn == nil {
+			return // not a static call
+		}
+		if len(call.Args) < 2 {
+			return // not enough arguments, e.g. called with return values of another function
+		}
+		if fn.FullName() == "errors.As" && !pointerToInterfaceOrError(pass, call.Args[1]) {
+			pass.Reportf(call.Pos(), "second argument to errors.As must be a pointer to an interface or a type implementing error")
+		}
+	})
+	return nil, nil
+}
+
+var errorType = types.Universe.Lookup("error").Type().Underlying().(*types.Interface)
+
+// pointerToInterfaceOrError reports whether the type of e is a pointer to an interface or a type implementing error,
+// or is the empty interface.
+func pointerToInterfaceOrError(pass *analysis.Pass, e ast.Expr) bool {
+	t := pass.TypesInfo.Types[e].Type
+	if it, ok := t.Underlying().(*types.Interface); ok && it.NumMethods() == 0 {
+		return true
+	}
+	pt, ok := t.Underlying().(*types.Pointer)
+	if !ok {
+		return false
+	}
+	_, ok = pt.Elem().Underlying().(*types.Interface)
+	return ok || types.Implements(pt.Elem(), errorType)
+}
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/inspect/inspect.go b/libgo/go/golang.org/x/tools/go/analysis/passes/inspect/inspect.go
index bd06549984a..8213f633135 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/inspect/inspect.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/inspect/inspect.go
@@ -8,7 +8,11 @@
 //
 // Example of use in another analysis:
 //
-//	import "golang.org/x/tools/go/analysis/passes/inspect"
+//	import (
+//		"golang.org/x/tools/go/analysis"
+//		"golang.org/x/tools/go/analysis/passes/inspect"
+//		"golang.org/x/tools/go/ast/inspector"
+//	)
 //
 //	var Analyzer = &analysis.Analyzer{
 //		...
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go b/libgo/go/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go
index b5161836a57..e88cf57d8f7 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go
@@ -45,6 +45,8 @@ var contextPackage = "context"
 // control-flow path from the call to a return statement and that path
 // does not "use" the cancel function.  Any reference to the variable
 // counts as a use, even within a nested function literal.
+// If the variable's scope is larger than the function
+// containing the assignment, we assume that other uses exist.
 //
 // checkLostCancel analyzes a single named or literal function.
 func run(pass *analysis.Pass) (interface{}, error) {
@@ -66,6 +68,15 @@ func run(pass *analysis.Pass) (interface{}, error) {
 }
 
 func runFunc(pass *analysis.Pass, node ast.Node) {
+	// Find scope of function node
+	var funcScope *types.Scope
+	switch v := node.(type) {
+	case *ast.FuncLit:
+		funcScope = pass.TypesInfo.Scopes[v.Type]
+	case *ast.FuncDecl:
+		funcScope = pass.TypesInfo.Scopes[v.Type]
+	}
+
 	// Maps each cancel variable to its defining ValueSpec/AssignStmt.
 	cancelvars := make(map[*types.Var]ast.Node)
 
@@ -114,7 +125,11 @@ func runFunc(pass *analysis.Pass, node ast.Node) {
 					"the cancel function returned by context.%s should be called, not discarded, to avoid a context leak",
 					n.(*ast.SelectorExpr).Sel.Name)
 			} else if v, ok := pass.TypesInfo.Uses[id].(*types.Var); ok {
-				cancelvars[v] = stmt
+				// If the cancel variable is defined outside function scope,
+				// do not analyze it.
+				if funcScope.Contains(v.Pos()) {
+					cancelvars[v] = stmt
+				}
 			} else if v, ok := pass.TypesInfo.Defs[id].(*types.Var); ok {
 				cancelvars[v] = stmt
 			}
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/printf/printf.go b/libgo/go/golang.org/x/tools/go/analysis/passes/printf/printf.go
index c0265aafeee..f59e95dc219 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/printf/printf.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/printf/printf.go
@@ -453,15 +453,23 @@ func printfNameAndKind(pass *analysis.Pass, call *ast.CallExpr) (fn *types.Func,
 }
 
 // isFormatter reports whether t satisfies fmt.Formatter.
-// Unlike fmt.Stringer, it's impossible to satisfy fmt.Formatter without importing fmt.
-func isFormatter(pass *analysis.Pass, t types.Type) bool {
-	for _, imp := range pass.Pkg.Imports() {
-		if imp.Path() == "fmt" {
-			formatter := imp.Scope().Lookup("Formatter").Type().Underlying().(*types.Interface)
-			return types.Implements(t, formatter)
-		}
+// The only interface method to look for is "Format(State, rune)".
+func isFormatter(typ types.Type) bool {
+	obj, _, _ := types.LookupFieldOrMethod(typ, false, nil, "Format")
+	fn, ok := obj.(*types.Func)
+	if !ok {
+		return false
 	}
-	return false
+	sig := fn.Type().(*types.Signature)
+	return sig.Params().Len() == 2 &&
+		sig.Results().Len() == 0 &&
+		isNamed(sig.Params().At(0).Type(), "fmt", "State") &&
+		types.Identical(sig.Params().At(1).Type(), types.Typ[types.Rune])
+}
+
+func isNamed(T types.Type, pkgpath, name string) bool {
+	named, ok := T.(*types.Named)
+	return ok && named.Obj().Pkg().Path() == pkgpath && named.Obj().Name() == name
 }
 
 // formatState holds the parsed representation of a printf directive such as "%3.*[4]d".
@@ -731,6 +739,7 @@ var printVerbs = []printVerb{
 	{'T', "-", anyType},
 	{'U', "-#", argRune | argInt},
 	{'v', allFlags, anyType},
+	{'w', noFlag, anyType},
 	{'x', sharpNumFlag, argRune | argInt | argString | argPointer},
 	{'X', sharpNumFlag, argRune | argInt | argString | argPointer},
 }
@@ -753,7 +762,7 @@ func okPrintfArg(pass *analysis.Pass, call *ast.CallExpr, state *formatState) (o
 	formatter := false
 	if state.argNum < len(call.Args) {
 		if tv, ok := pass.TypesInfo.Types[call.Args[state.argNum]]; ok {
-			formatter = isFormatter(pass, tv.Type)
+			formatter = isFormatter(tv.Type)
 		}
 	}
 
@@ -831,7 +840,7 @@ func recursiveStringer(pass *analysis.Pass, e ast.Expr) bool {
 	typ := pass.TypesInfo.Types[e].Type
 
 	// It's unlikely to be a recursive stringer if it has a Format method.
-	if isFormatter(pass, typ) {
+	if isFormatter(typ) {
 		return false
 	}
 
@@ -847,20 +856,28 @@ func recursiveStringer(pass *analysis.Pass, e ast.Expr) bool {
 		return false
 	}
 
-	// Is it the receiver r, or &r?
-	recv := stringMethod.Type().(*types.Signature).Recv()
-	if recv == nil {
+	sig := stringMethod.Type().(*types.Signature)
+	if !isStringer(sig) {
 		return false
 	}
+
+	// Is it the receiver r, or &r?
 	if u, ok := e.(*ast.UnaryExpr); ok && u.Op == token.AND {
 		e = u.X // strip off & from &r
 	}
 	if id, ok := e.(*ast.Ident); ok {
-		return pass.TypesInfo.Uses[id] == recv
+		return pass.TypesInfo.Uses[id] == sig.Recv()
 	}
 	return false
 }
 
+// isStringer reports whether the method signature matches the String() definition in fmt.Stringer.
+func isStringer(sig *types.Signature) bool {
+	return sig.Params().Len() == 0 &&
+		sig.Results().Len() == 1 &&
+		sig.Results().At(0).Type() == types.Typ[types.String]
+}
+
 // isFunctionValue reports whether the expression is a function as opposed to a function call.
 // It is almost always a mistake to print a function value.
 func isFunctionValue(pass *analysis.Pass, e ast.Expr) bool {
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/printf/types.go b/libgo/go/golang.org/x/tools/go/analysis/passes/printf/types.go
index 87523a19c67..12286fd5df5 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/printf/types.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/printf/types.go
@@ -2,7 +2,6 @@ package printf
 
 import (
 	"go/ast"
-	"go/build"
 	"go/types"
 
 	"golang.org/x/tools/go/analysis"
@@ -39,7 +38,7 @@ func matchArgTypeInternal(pass *analysis.Pass, t printfArgType, typ types.Type,
 		}
 	}
 	// If the type implements fmt.Formatter, we have nothing to check.
-	if isFormatter(pass, typ) {
+	if isFormatter(typ) {
 		return true
 	}
 	// If we can use a string, might arg (dynamically) implement the Stringer or Error interface?
@@ -235,5 +234,3 @@ func matchStructArgType(pass *analysis.Pass, t printfArgType, typ *types.Struct,
 	}
 	return true
 }
-
-var archSizes = types.SizesFor("gccgo", build.Default.GOARCH)
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/shift/shift.go b/libgo/go/golang.org/x/tools/go/analysis/passes/shift/shift.go
index 4142ac342ad..39f54573c9f 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/shift/shift.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/shift/shift.go
@@ -12,10 +12,8 @@ package shift
 
 import (
 	"go/ast"
-	"go/build"
 	"go/constant"
 	"go/token"
-	"go/types"
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
@@ -93,36 +91,9 @@ func checkLongShift(pass *analysis.Pass, node ast.Node, x, y ast.Expr) {
 	if t == nil {
 		return
 	}
-	b, ok := t.Underlying().(*types.Basic)
-	if !ok {
-		return
-	}
-	var size int64
-	switch b.Kind() {
-	case types.Uint8, types.Int8:
-		size = 8
-	case types.Uint16, types.Int16:
-		size = 16
-	case types.Uint32, types.Int32:
-		size = 32
-	case types.Uint64, types.Int64:
-		size = 64
-	case types.Int, types.Uint:
-		size = uintBitSize
-	case types.Uintptr:
-		size = uintptrBitSize
-	default:
-		return
-	}
+	size := 8 * pass.TypesSizes.Sizeof(t)
 	if amt >= size {
 		ident := analysisutil.Format(pass.Fset, x)
 		pass.Reportf(node.Pos(), "%s (%d bits) too small for shift of %d", ident, size, amt)
 	}
 }
-
-var (
-	uintBitSize    = 8 * archSizes.Sizeof(types.Typ[types.Uint])
-	uintptrBitSize = 8 * archSizes.Sizeof(types.Typ[types.Uintptr])
-)
-
-var archSizes = types.SizesFor("gccgo", build.Default.GOARCH)
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go b/libgo/go/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go
index 83495112243..bc1db7e4c2e 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go
@@ -8,7 +8,6 @@ package stdmethods
 
 import (
 	"go/ast"
-	"go/token"
 	"go/types"
 	"strings"
 
@@ -117,6 +116,13 @@ func canonicalMethod(pass *analysis.Pass, id *ast.Ident) {
 	args := sign.Params()
 	results := sign.Results()
 
+	// Special case: WriteTo with more than one argument,
+	// not trying at all to implement io.WriterTo,
+	// comes up often enough to skip.
+	if id.Name == "WriteTo" && args.Len() > 1 {
+		return
+	}
+
 	// Do the =s (if any) all match?
 	if !matchParams(pass, expect.args, args, "=") || !matchParams(pass, expect.results, results, "=") {
 		return
@@ -163,7 +169,7 @@ func matchParams(pass *analysis.Pass, expect []string, actual *types.Tuple, pref
 		if i >= actual.Len() {
 			return false
 		}
-		if !matchParamType(pass.Fset, pass.Pkg, x, actual.At(i).Type()) {
+		if !matchParamType(x, actual.At(i).Type()) {
 			return false
 		}
 	}
@@ -174,13 +180,8 @@ func matchParams(pass *analysis.Pass, expect []string, actual *types.Tuple, pref
 }
 
 // Does this one type match?
-func matchParamType(fset *token.FileSet, pkg *types.Package, expect string, actual types.Type) bool {
+func matchParamType(expect string, actual types.Type) bool {
 	expect = strings.TrimPrefix(expect, "=")
-	// Strip package name if we're in that package.
-	if n := len(pkg.Name()); len(expect) > n && expect[:n] == pkg.Name() && expect[n] == '.' {
-		expect = expect[n+1:]
-	}
-
 	// Overkill but easy.
 	return typeString(actual) == expect
 }
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/structtag/structtag.go b/libgo/go/golang.org/x/tools/go/analysis/passes/structtag/structtag.go
index 2b67c376bab..acc6e6c770d 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/structtag/structtag.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/structtag/structtag.go
@@ -41,7 +41,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 	}
 	inspect.Preorder(nodeFilter, func(n ast.Node) {
 		styp := pass.TypesInfo.Types[n.(*ast.StructType)].Type.(*types.Struct)
-		var seen map[[2]string]token.Pos
+		var seen namesSeen
 		for i := 0; i < styp.NumFields(); i++ {
 			field := styp.Field(i)
 			tag := styp.Tag(i)
@@ -51,13 +51,47 @@ func run(pass *analysis.Pass) (interface{}, error) {
 	return nil, nil
 }
 
+// namesSeen keeps track of encoding tags by their key, name, and nested level
+// from the initial struct. The level is taken into account because equal
+// encoding key names only conflict when at the same level; otherwise, the lower
+// level shadows the higher level.
+type namesSeen map[uniqueName]token.Pos
+
+type uniqueName struct {
+	key   string // "xml" or "json"
+	name  string // the encoding name
+	level int    // anonymous struct nesting level
+}
+
+func (s *namesSeen) Get(key, name string, level int) (token.Pos, bool) {
+	if *s == nil {
+		*s = make(map[uniqueName]token.Pos)
+	}
+	pos, ok := (*s)[uniqueName{key, name, level}]
+	return pos, ok
+}
+
+func (s *namesSeen) Set(key, name string, level int, pos token.Pos) {
+	if *s == nil {
+		*s = make(map[uniqueName]token.Pos)
+	}
+	(*s)[uniqueName{key, name, level}] = pos
+}
+
 var checkTagDups = []string{"json", "xml"}
 var checkTagSpaces = map[string]bool{"json": true, "xml": true, "asn1": true}
 
 // checkCanonicalFieldTag checks a single struct field tag.
-func checkCanonicalFieldTag(pass *analysis.Pass, field *types.Var, tag string, seen *map[[2]string]token.Pos) {
+func checkCanonicalFieldTag(pass *analysis.Pass, field *types.Var, tag string, seen *namesSeen) {
+	switch pass.Pkg.Path() {
+	case "encoding/json", "encoding/xml":
+		// These packages know how to use their own APIs.
+		// Sometimes they are testing what happens to incorrect programs.
+		return
+	}
+
 	for _, key := range checkTagDups {
-		checkTagDuplicates(pass, tag, key, field, field, seen)
+		checkTagDuplicates(pass, tag, key, field, field, seen, 1)
 	}
 
 	if err := validateStructTag(tag); err != nil {
@@ -88,28 +122,29 @@ func checkCanonicalFieldTag(pass *analysis.Pass, field *types.Var, tag string, s
 // checkTagDuplicates checks a single struct field tag to see if any tags are
 // duplicated. nearest is the field that's closest to the field being checked,
 // while still being part of the top-level struct type.
-func checkTagDuplicates(pass *analysis.Pass, tag, key string, nearest, field *types.Var, seen *map[[2]string]token.Pos) {
+func checkTagDuplicates(pass *analysis.Pass, tag, key string, nearest, field *types.Var, seen *namesSeen, level int) {
 	val := reflect.StructTag(tag).Get(key)
 	if val == "-" {
 		// Ignored, even if the field is anonymous.
 		return
 	}
 	if val == "" || val[0] == ',' {
-		if field.Anonymous() {
-			typ, ok := field.Type().Underlying().(*types.Struct)
-			if !ok {
-				return
-			}
-			for i := 0; i < typ.NumFields(); i++ {
-				field := typ.Field(i)
-				if !field.Exported() {
-					continue
-				}
-				tag := typ.Tag(i)
-				checkTagDuplicates(pass, tag, key, nearest, field, seen)
+		if !field.Anonymous() {
+			// Ignored if the field isn't anonymous.
+			return
+		}
+		typ, ok := field.Type().Underlying().(*types.Struct)
+		if !ok {
+			return
+		}
+		for i := 0; i < typ.NumFields(); i++ {
+			field := typ.Field(i)
+			if !field.Exported() {
+				continue
 			}
+			tag := typ.Tag(i)
+			checkTagDuplicates(pass, tag, key, nearest, field, seen, level+1)
 		}
-		// Ignored if the field isn't anonymous.
 		return
 	}
 	if key == "xml" && field.Name() == "XMLName" {
@@ -132,10 +167,7 @@ func checkTagDuplicates(pass *analysis.Pass, tag, key string, nearest, field *ty
 		}
 		val = val[:i]
 	}
-	if *seen == nil {
-		*seen = map[[2]string]token.Pos{}
-	}
-	if pos, ok := (*seen)[[2]string{key, val}]; ok {
+	if pos, ok := seen.Get(key, val, level); ok {
 		alsoPos := pass.Fset.Position(pos)
 		alsoPos.Column = 0
 
@@ -154,7 +186,7 @@ func checkTagDuplicates(pass *analysis.Pass, tag, key string, nearest, field *ty
 
 		pass.Reportf(nearest.Pos(), "struct field %s repeats %s tag %q also at %s", field.Name(), key, val, alsoPos)
 	} else {
-		(*seen)[[2]string{key, val}] = field.Pos()
+		seen.Set(key, val, level, field.Pos())
 	}
 }
 
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/tests/tests.go b/libgo/go/golang.org/x/tools/go/analysis/passes/tests/tests.go
index 35b0a3e7cc2..8232276186a 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/tests/tests.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/tests/tests.go
@@ -20,7 +20,10 @@ const Doc = `check for common mistaken usages of tests and examples
 
 The tests checker walks Test, Benchmark and Example functions checking
 malformed names, wrong signatures and examples documenting non-existent
-identifiers.`
+identifiers.
+
+Please see the documentation for package testing in golang.org/pkg/testing
+for the conventions that are enforced for Tests, Benchmarks, and Examples.`
 
 var Analyzer = &analysis.Analyzer{
 	Name: "tests",
@@ -84,23 +87,25 @@ func isTestParam(typ ast.Expr, wantType string) bool {
 	return false
 }
 
-func lookup(pkg *types.Package, name string) types.Object {
+func lookup(pkg *types.Package, name string) []types.Object {
 	if o := pkg.Scope().Lookup(name); o != nil {
-		return o
-	}
-
-	// If this package is ".../foo_test" and it imports a package
-	// ".../foo", try looking in the latter package.
-	// This heuristic should work even on build systems that do not
-	// record any special link between the packages.
-	if basePath := strings.TrimSuffix(pkg.Path(), "_test"); basePath != pkg.Path() {
-		for _, imp := range pkg.Imports() {
-			if imp.Path() == basePath {
-				return imp.Scope().Lookup(name)
-			}
+		return []types.Object{o}
+	}
+
+	var ret []types.Object
+	// Search through the imports to see if any of them define name.
+	// It's hard to tell in general which package is being tested, so
+	// for the purposes of the analysis, allow the object to appear
+	// in any of the imports. This guarantees there are no false positives
+	// because the example needs to use the object so it must be defined
+	// in the package or one if its imports. On the other hand, false
+	// negatives are possible, but should be rare.
+	for _, imp := range pkg.Imports() {
+		if obj := imp.Scope().Lookup(name); obj != nil {
+			ret = append(ret, obj)
 		}
 	}
-	return nil
+	return ret
 }
 
 func checkExample(pass *analysis.Pass, fn *ast.FuncDecl) {
@@ -121,9 +126,9 @@ func checkExample(pass *analysis.Pass, fn *ast.FuncDecl) {
 		exName = strings.TrimPrefix(fnName, "Example")
 		elems  = strings.SplitN(exName, "_", 3)
 		ident  = elems[0]
-		obj    = lookup(pass.Pkg, ident)
+		objs   = lookup(pass.Pkg, ident)
 	)
-	if ident != "" && obj == nil {
+	if ident != "" && len(objs) == 0 {
 		// Check ExampleFoo and ExampleBadFoo.
 		pass.Reportf(fn.Pos(), "%s refers to unknown identifier: %s", fnName, ident)
 		// Abort since obj is absent and no subsequent checks can be performed.
@@ -145,7 +150,15 @@ func checkExample(pass *analysis.Pass, fn *ast.FuncDecl) {
 	mmbr := elems[1]
 	if !isExampleSuffix(mmbr) {
 		// Check ExampleFoo_Method and ExampleFoo_BadMethod.
-		if obj, _, _ := types.LookupFieldOrMethod(obj.Type(), true, obj.Pkg(), mmbr); obj == nil {
+		found := false
+		// Check if Foo.Method exists in this package or its imports.
+		for _, obj := range objs {
+			if obj, _, _ := types.LookupFieldOrMethod(obj.Type(), true, obj.Pkg(), mmbr); obj != nil {
+				found = true
+				break
+			}
+		}
+		if !found {
 			pass.Reportf(fn.Pos(), "%s refers to unknown field or method: %s.%s", fnName, ident, mmbr)
 		}
 	}
diff --git a/libgo/go/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go b/libgo/go/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go
index 6cf4358ab9a..d019ecef15a 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go
@@ -29,6 +29,13 @@ var Analyzer = &analysis.Analyzer{
 }
 
 func run(pass *analysis.Pass) (interface{}, error) {
+	switch pass.Pkg.Path() {
+	case "encoding/gob", "encoding/json", "encoding/xml":
+		// These packages know how to use their own APIs.
+		// Sometimes they are testing what happens to incorrect programs.
+		return nil, nil
+	}
+
 	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
 
 	nodeFilter := []ast.Node{
diff --git a/libgo/go/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go b/libgo/go/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
index 5943c99e13b..b4fda19ecaa 100644
--- a/libgo/go/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
+++ b/libgo/go/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
@@ -329,6 +329,7 @@ func run(fset *token.FileSet, cfg *Config, analyzers []*analysis.Analyzer) ([]re
 				OtherFiles:        cfg.NonGoFiles,
 				Pkg:               pkg,
 				TypesInfo:         info,
+				TypesSizes:        tc.Sizes,
 				ResultOf:          inputs,
 				Report:            func(d analysis.Diagnostic) { act.diagnostics = append(act.diagnostics, d) },
 				ImportObjectFact:  facts.ImportObjectFact,
diff --git a/libgo/go/golang.org/x/tools/go/ast/inspector/inspector.go b/libgo/go/golang.org/x/tools/go/ast/inspector/inspector.go
index db88a951090..ddbdd3f08fc 100644
--- a/libgo/go/golang.org/x/tools/go/ast/inspector/inspector.go
+++ b/libgo/go/golang.org/x/tools/go/ast/inspector/inspector.go
@@ -14,7 +14,7 @@
 // Experiments suggest the inspector's traversals are about 2.5x faster
 // than ast.Inspect, but it may take around 5 traversals for this
 // benefit to amortize the inspector's construction cost.
-// If efficiency is the primary concern, do not use use Inspector for
+// If efficiency is the primary concern, do not use Inspector for
 // one-off traversals.
 package inspector