cmd/vendor: update to golang.org/x/tools@139d099f

Mainly to pull the fix for the regression in #28792.

Change-Id: If71ae783fd9a9e3935186b49fdf501ba098235a2
Reviewed-on: https://go-review.googlesource.com/c/150161
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

src/cmd/vendor/golang.org/x/tools/go/analysis/passes/composite/composite.go

@@ -16,7 +16,7 @@ import (
 	"golang.org/x/tools/go/ast/inspector"
 )
 
-const Doc = `checked for unkeyed composite literals
+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

src/cmd/vendor/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go

@@ -93,7 +93,9 @@ func runFunc(pass *analysis.Pass, node ast.Node) {
 		//   ctx, cancel     = context.WithCancel(...)
 		//   var ctx, cancel = context.WithCancel(...)
 		//
-		if isContextWithCancel(pass.TypesInfo, n) && isCall(stack[len(stack)-2]) {
+		if !isContextWithCancel(pass.TypesInfo, n) || !isCall(stack[len(stack)-2]) {
+			return true
+		}
 		var id *ast.Ident // id of cancel var
 		stmt := stack[len(stack)-3]
 		switch stmt := stmt.(type) {
@@ -117,8 +119,6 @@ func runFunc(pass *analysis.Pass, node ast.Node) {
 				cancelvars[v] = stmt
 			}
 		}
-		}
-
 		return true
 	})
 
@@ -179,9 +179,15 @@ func hasImport(pkg *types.Package, path string) bool {
 // isContextWithCancel reports whether n is one of the qualified identifiers
 // context.With{Cancel,Timeout,Deadline}.
 func isContextWithCancel(info *types.Info, n ast.Node) bool {
-	if sel, ok := n.(*ast.SelectorExpr); ok {
+	sel, ok := n.(*ast.SelectorExpr)
+	if !ok {
+		return false
+	}
 	switch sel.Sel.Name {
 	case "WithCancel", "WithTimeout", "WithDeadline":
+	default:
+		return false
+	}
 	if x, ok := sel.X.(*ast.Ident); ok {
 		if pkgname, ok := info.Uses[x].(*types.PkgName); ok {
 			return pkgname.Imported().Path() == contextPackage
@@ -190,8 +196,6 @@ func isContextWithCancel(info *types.Info, n ast.Node) bool {
 		// Just check the local package name (heuristic).
 		return x.Name == "context"
 	}
-		}
-	}
 	return false
 }
 
@@ -270,7 +274,9 @@ outer:
 	var search func(blocks []*cfg.Block) *ast.ReturnStmt
 	search = func(blocks []*cfg.Block) *ast.ReturnStmt {
 		for _, b := range blocks {
-			if !seen[b] {
+			if seen[b] {
+				continue
+			}
 			seen[b] = true
 
 			// Prune the search if the block uses v.
@@ -294,7 +300,6 @@ outer:
 				return ret
 			}
 		}
-		}
 		return nil
 	}
 	return search(defblock.Succs)

src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go

@@ -131,7 +131,7 @@ func canonicalMethod(pass *analysis.Pass, id *ast.Ident) {
 			expectFmt += " (" + argjoin(expect.results) + ")"
 		}
 
-		actual := types.TypeString(sign, (*types.Package).Name)
+		actual := typeString(sign)
 		actual = strings.TrimPrefix(actual, "func")
 		actual = id.Name + actual
 
@@ -139,6 +139,10 @@ func canonicalMethod(pass *analysis.Pass, id *ast.Ident) {
 	}
 }
 
+func typeString(typ types.Type) string {
+	return types.TypeString(typ, (*types.Package).Name)
+}
+
 func argjoin(x []string) string {
 	y := make([]string, len(x))
 	for i, s := range x {
@@ -178,5 +182,5 @@ func matchParamType(fset *token.FileSet, pkg *types.Package, expect string, actu
 	}
 
 	// Overkill but easy.
-	return actual.String() == expect
+	return typeString(actual) == expect
 }

src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unsafeptr/unsafeptr.go

@@ -62,8 +62,9 @@ func isSafeUintptr(info *types.Info, x ast.Expr) bool {
 		return isSafeUintptr(info, x.X)
 
 	case *ast.SelectorExpr:
-		switch x.Sel.Name {
-		case "Data":
+		if x.Sel.Name != "Data" {
+			break
+		}
 		// reflect.SliceHeader and reflect.StringHeader are okay,
 		// but only if they are pointing at a real slice or string.
 		// It's not okay to do:
@@ -86,7 +87,6 @@ func isSafeUintptr(info *types.Info, x ast.Expr) bool {
 				}
 			}
 		}
-		}
 
 	case *ast.CallExpr:
 		switch len(x.Args) {