diff --git a/gopls/internal/regtest/diagnostics/builtin_test.go b/gopls/internal/regtest/diagnostics/builtin_test.go
new file mode 100644
index 0000000..775e7ec
--- /dev/null
+++ b/gopls/internal/regtest/diagnostics/builtin_test.go
@@ -0,0 +1,38 @@
+// Copyright 2021 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.
+
+package diagnostics
+
+import (
+	"strings"
+	"testing"
+
+	. "golang.org/x/tools/internal/lsp/regtest"
+)
+
+func TestIssue44866(t *testing.T) {
+	src := `
+-- go.mod --
+module mod.com
+
+go 1.12
+-- a.go --
+package a
+
+const (
+	c = iota
+)
+`
+	Run(t, src, func(t *testing.T, env *Env) {
+		env.OpenFile("a.go")
+		name, _ := env.GoToDefinition("a.go", env.RegexpSearch("a.go", "iota"))
+		if !strings.HasSuffix(name, "builtin.go") {
+			t.Fatalf("jumped to %q, want builtin.go", name)
+		}
+		env.Await(OnceMet(
+			env.DoneWithOpen(),
+			NoDiagnostics("builtin.go"),
+		))
+	})
+}
diff --git a/internal/lsp/cache/snapshot.go b/internal/lsp/cache/snapshot.go
index 3215b7e..7c8dfae 100644
--- a/internal/lsp/cache/snapshot.go
+++ b/internal/lsp/cache/snapshot.go
@@ -51,7 +51,7 @@
 	generation *memoize.Generation
 
 	// builtin pins the AST and package for builtin.go in memory.
-	builtin *builtinPackageHandle
+	builtin *builtinPackageData
 
 	// The snapshot's initialization state is controlled by the fields below.
 	//
@@ -1361,10 +1361,6 @@
 		newGen.Inherit(s.workspaceDirHandle)
 	}
 
-	if s.builtin != nil {
-		newGen.Inherit(s.builtin.handle)
-	}
-
 	// Copy all of the FileHandles.
 	for k, v := range s.files {
 		result.files[k] = v
@@ -1755,12 +1751,18 @@
 	if s.builtin == nil {
 		return nil, errors.Errorf("no builtin package for view %s", s.view.name)
 	}
-	d, err := s.builtin.handle.Get(ctx, s.generation, s)
+	return s.builtin.parsed, s.builtin.err
+}
+
+func (s *snapshot) IsBuiltin(ctx context.Context, uri span.URI) bool {
+	builtin, err := s.BuiltinPackage(ctx)
 	if err != nil {
-		return nil, err
+		event.Error(ctx, "checking for builtin", err)
+		return false
 	}
-	data := d.(*builtinPackageData)
-	return data.parsed, data.err
+	// We should always get the builtin URI in a canonical form, so use simple
+	// string comparison here. span.CompareURI is too expensive.
+	return builtin.ParsedFile.URI == uri
 }
 
 func (s *snapshot) buildBuiltinPackage(ctx context.Context, goFiles []string) error {
@@ -1775,31 +1777,30 @@
 	if err != nil {
 		return err
 	}
-	h := s.generation.Bind(fh.FileIdentity(), func(ctx context.Context, arg memoize.Arg) interface{} {
-		snapshot := arg.(*snapshot)
-
-		pgh := snapshot.parseGoHandle(ctx, fh, source.ParseFull)
-		pgf, _, err := snapshot.parseGo(ctx, pgh)
-		if err != nil {
-			return &builtinPackageData{err: err}
-		}
-		pkg, err := ast.NewPackage(snapshot.view.session.cache.fset, map[string]*ast.File{
-			pgf.URI.Filename(): pgf.File,
-		}, nil, nil)
-		if err != nil {
-			return &builtinPackageData{err: err}
-		}
-		return &builtinPackageData{
-			parsed: &source.BuiltinPackage{
-				ParsedFile: pgf,
-				Package:    pkg,
-			},
-		}
-	}, nil)
-	s.builtin = &builtinPackageHandle{handle: h}
+	s.builtin = buildBuiltinPackage(ctx, fh, s)
 	return nil
 }
 
+func buildBuiltinPackage(ctx context.Context, fh *fileHandle, snapshot *snapshot) *builtinPackageData {
+	pgh := snapshot.parseGoHandle(ctx, fh, source.ParseFull)
+	pgf, _, err := snapshot.parseGo(ctx, pgh)
+	if err != nil {
+		return &builtinPackageData{err: err}
+	}
+	pkg, err := ast.NewPackage(snapshot.view.session.cache.fset, map[string]*ast.File{
+		pgf.URI.Filename(): pgf.File,
+	}, nil, nil)
+	if err != nil {
+		return &builtinPackageData{err: err}
+	}
+	return &builtinPackageData{
+		parsed: &source.BuiltinPackage{
+			ParsedFile: pgf,
+			Package:    pkg,
+		},
+	}
+}
+
 // BuildGoplsMod generates a go.mod file for all modules in the workspace. It
 // bypasses any existing gopls.mod.
 func BuildGoplsMod(ctx context.Context, root span.URI, s source.Snapshot) (*modfile.File, error) {
diff --git a/internal/lsp/diagnostics.go b/internal/lsp/diagnostics.go
index f93e525..f892910 100644
--- a/internal/lsp/diagnostics.go
+++ b/internal/lsp/diagnostics.go
@@ -121,6 +121,7 @@
 func (s *Server) diagnoseChangedFiles(ctx context.Context, snapshot source.Snapshot, uris []span.URI, onDisk bool) {
 	ctx, done := event.Start(ctx, "Server.diagnoseChangedFiles", tag.Snapshot.Of(snapshot.ID()))
 	defer done()
+
 	packages := make(map[source.Package]struct{})
 	for _, uri := range uris {
 		// If the change is only on-disk and the file is not open, don't
@@ -133,6 +134,11 @@
 		if snapshot.FindFile(uri) == nil {
 			continue
 		}
+		// Don't call PackagesForFile for builtin.go, as it results in a
+		// command-line-arguments load.
+		if snapshot.IsBuiltin(ctx, uri) {
+			continue
+		}
 		pkgs, err := snapshot.PackagesForFile(ctx, uri, source.TypecheckFull)
 		if err != nil {
 			// TODO (findleyr): we should probably do something with the error here,
@@ -393,6 +399,10 @@
 	if fh.Kind() != source.Go {
 		return nil
 	}
+	// builtin files won't have a package, but they are never orphaned.
+	if snapshot.IsBuiltin(ctx, fh.URI()) {
+		return nil
+	}
 	pkgs, err := snapshot.PackagesForFile(ctx, fh.URI(), source.TypecheckWorkspace)
 	if len(pkgs) > 0 || err == nil {
 		return nil
diff --git a/internal/lsp/fake/editor.go b/internal/lsp/fake/editor.go
index f10ea44..cceebe3 100644
--- a/internal/lsp/fake/editor.go
+++ b/internal/lsp/fake/editor.go
@@ -693,7 +693,7 @@
 }
 
 // GoToDefinition jumps to the definition of the symbol at the given position
-// in an open buffer.
+// in an open buffer. It returns the path and position of the resulting jump.
 func (e *Editor) GoToDefinition(ctx context.Context, path string, pos Pos) (string, Pos, error) {
 	if err := e.checkBufferPosition(path, pos); err != nil {
 		return "", Pos{}, err
diff --git a/internal/lsp/regtest/wrappers.go b/internal/lsp/regtest/wrappers.go
index 2038849..0137218 100644
--- a/internal/lsp/regtest/wrappers.go
+++ b/internal/lsp/regtest/wrappers.go
@@ -156,7 +156,7 @@
 }
 
 // GoToDefinition goes to definition in the editor, calling t.Fatal on any
-// error.
+// error. It returns the path and position of the resulting jump.
 func (e *Env) GoToDefinition(name string, pos fake.Pos) (string, fake.Pos) {
 	e.T.Helper()
 	n, p, err := e.Editor.GoToDefinition(e.Ctx, name, pos)
diff --git a/internal/lsp/source/view.go b/internal/lsp/source/view.go
index 412866c..2595823 100644
--- a/internal/lsp/source/view.go
+++ b/internal/lsp/source/view.go
@@ -128,6 +128,9 @@
 	// BuiltinPackage returns information about the special builtin package.
 	BuiltinPackage(ctx context.Context) (*BuiltinPackage, error)
 
+	// IsBuiltin reports whether uri is part of the builtin package.
+	IsBuiltin(ctx context.Context, uri span.URI) bool
+
 	// PackagesForFile returns the packages that this file belongs to, checked
 	// in mode.
 	PackagesForFile(ctx context.Context, uri span.URI, mode TypecheckMode) ([]Package, error)