diff --git a/go/ast/astutil/imports.go b/go/ast/astutil/imports.go
index 7d793ffa..2e81f4d3 100644
--- a/go/ast/astutil/imports.go
+++ b/go/ast/astutil/imports.go
@@ -160,6 +160,9 @@ func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added
 			first = gen
 			continue // Don't touch the first one.
 		}
+		// We now know there is more than one package in this import
+		// declaration. Ensure that it ends up parenthesized.
+		first.Lparen = first.Pos()
 		// Move the imports of the other import declaration to the first one.
 		for _, spec := range gen.Specs {
 			spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
diff --git a/go/ast/astutil/imports_test.go b/go/ast/astutil/imports_test.go
index c9f80df7..67dd5565 100644
--- a/go/ast/astutil/imports_test.go
+++ b/go/ast/astutil/imports_test.go
@@ -509,6 +509,42 @@ import "C"
 // Comment
 import "C"
 import "bufio"
+`,
+	},
+	{
+		name: `issue 17212 several single-import lines with shared prefix ending in a slash`,
+		pkg:  "net/http",
+		in: `package main
+
+import "bufio"
+import "net/url"
+`,
+		out: `package main
+
+import (
+	"bufio"
+	"net/http"
+	"net/url"
+)
+`,
+	},
+	{
+		name: `issue 17212 block imports lines with shared prefix ending in a slash`,
+		pkg:  "net/http",
+		in: `package main
+
+import (
+	"bufio"
+	"net/url"
+)
+`,
+		out: `package main
+
+import (
+	"bufio"
+	"net/http"
+	"net/url"
+)
 `,
 	},
 	{