diff --git a/go/ast/astutil/imports.go b/go/ast/astutil/imports.go
index cfaa864a..070ff35d 100644
--- a/go/ast/astutil/imports.go
+++ b/go/ast/astutil/imports.go
@@ -150,7 +150,8 @@ func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added
 
 	// Merge all the import declarations into the first one.
 	var first *ast.GenDecl
-	for i, decl := range f.Decls {
+	for i := 0; i < len(f.Decls); i++ {
+		decl := f.Decls[i]
 		gen, ok := decl.(*ast.GenDecl)
 		if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
 			continue
@@ -165,6 +166,7 @@ func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added
 			first.Specs = append(first.Specs, spec)
 		}
 		f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
+		i--
 	}
 
 	return true
diff --git a/go/ast/astutil/imports_test.go b/go/ast/astutil/imports_test.go
index 3f6d00dc..eb00e47b 100644
--- a/go/ast/astutil/imports_test.go
+++ b/go/ast/astutil/imports_test.go
@@ -509,6 +509,25 @@ import "C"
 // Comment
 import "C"
 import "bufio"
+`,
+	},
+	{
+		name: `issue 17213 many single-import lines`,
+		pkg:  "fmt",
+		in: `package main
+
+import "bufio"
+import "bytes"
+import "errors"
+`,
+		out: `package main
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+)
 `,
 	},
 }