diff --git a/go/analysis/analysistest/analysistest.go b/go/analysis/analysistest/analysistest.go
index 25062c68..ad979c14 100644
--- a/go/analysis/analysistest/analysistest.go
+++ b/go/analysis/analysistest/analysistest.go
@@ -263,6 +263,9 @@ func check(t Testing, gopath string, pass *analysis.Pass, diagnostics []analysis
 
 	// Check the facts match expectations.
 	// Report errors in lexical order for determinism.
+	// (It's only deterministic within each file, not across files,
+	// because go/packages does not guarantee file.Pos is ascending
+	// across the files of a single compilation unit.)
 	var objects []types.Object
 	for obj := range facts {
 		objects = append(objects, obj)
diff --git a/go/analysis/passes/copylock/copylock.go b/go/analysis/passes/copylock/copylock.go
index e684cd37..c199c2ea 100644
--- a/go/analysis/passes/copylock/copylock.go
+++ b/go/analysis/passes/copylock/copylock.go
@@ -258,6 +258,15 @@ func lockPath(tpkg *types.Package, typ types.Type) typePath {
 		return []types.Type{typ}
 	}
 
+	// In go1.10, sync.noCopy did not implement Locker.
+	// (The Unlock method was added only in CL 121876.)
+	// TODO(adonovan): remove workaround when we drop go1.10.
+	if named, ok := typ.(*types.Named); ok &&
+		named.Obj().Name() == "noCopy" &&
+		named.Obj().Pkg().Path() == "sync" {
+		return []types.Type{typ}
+	}
+
 	nfields := styp.NumFields()
 	for i := 0; i < nfields; i++ {
 		ftyp := styp.Field(i).Type()
diff --git a/go/analysis/passes/copylock/copylock_test.go b/go/analysis/passes/copylock/copylock_test.go
index 3e4ca122..acbdb52a 100644
--- a/go/analysis/passes/copylock/copylock_test.go
+++ b/go/analysis/passes/copylock/copylock_test.go
@@ -7,7 +7,7 @@ import (
 	"golang.org/x/tools/go/analysis/passes/copylock"
 )
 
-func TestFromFileSystem(t *testing.T) {
+func Test(t *testing.T) {
 	testdata := analysistest.TestData()
 	analysistest.Run(t, testdata, copylock.Analyzer, "a")
 }