Add goimports option to simplify code like gofmt -s does

Author: dottedmag

cmd/goimports/goimports.go

@@ -54,6 +54,7 @@ func init() {
 	flag.StringVar(&options.LocalPrefix, "local", "", "put imports beginning with this string after 3rd-party packages; comma-separated list")
 	flag.BoolVar(&options.FormatOnly, "format-only", false, "if true, don't fix imports and only format. In this mode, goimports is effectively gofmt, with the addition that imports are grouped into sections.")
 	flag.BoolVar(&options.MergeAll, "merge-all", false, "if true, merge all imports into a single group")
+	flag.BoolVar(&options.Simplify, "s", false, "if true, simplify code like gofmt -s does")
 }
 
 func report(err error) {

internal/imports/fix_test.go

@@ -2999,6 +2999,26 @@ import (
 	}.processTest(t, "golang.org/fake", "x.go", nil, &Options{MergeAll: true}, want)
 }
 
+func TestSimplify(t *testing.T) {
+	const input = `package main
+
+var a = []foo{foo{}}
+`
+	const want = `package main
+
+var a = []foo{{}}
+`
+
+	testConfig{
+		modules: []packagestest.Module{
+			{
+				Name:  "golang.org/fake",
+				Files: fm{"x.go": input},
+			},
+		},
+	}.processTest(t, "golang.org/fake", "x.go", nil, &Options{Simplify: true}, want)
+}
+
 func TestSymbolSearchStarvation(t *testing.T) {
 	// This test verifies the fix for golang/go#67923: searching through
 	// candidates should not starve when the context is cancelled.

internal/imports/imports.go

@@ -36,6 +36,8 @@ type Options struct {
 
 	MergeAll bool // Merge all imports into a single group
 
+	Simplify bool // Simplify code like gofmt -s
+
 	Fragment  bool // Accept fragment of a source file (no package statement)
 	AllErrors bool // Report all errors (not just the first 10 on different lines)
 
@@ -135,6 +137,10 @@ func formatFile(fset *token.FileSet, file *ast.File, src []byte, adjust func(ori
 
 	}
 
+	if opt.Simplify {
+		simplify(file)
+	}
+
 	printerMode := printer.UseSpaces
 	if opt.TabIndent {
 		printerMode |= printer.TabIndent