zig fmt: Fix callconv rewriting for extern + string

Closes #4473

2 files changed, 3 insertions, 0 deletions

diff --git a/lib/std/zig/parser_test.zig b/lib/std/zig/parser_test.zig
index 28bf0c9ed5..5f28dd3b06 100644
--- a/lib/std/zig/parser_test.zig
+++ b/lib/std/zig/parser_test.zig
@@ -92,10 +92,12 @@ test "zig fmt: convert extern/nakedcc/stdcallcc into callconv(...)" {
         \\nakedcc fn foo1() void {}
         \\stdcallcc fn foo2() void {}
         \\extern fn foo3() void {}
+        \\extern "mylib" fn foo4() void {}
     ,
         \\fn foo1() callconv(.Naked) void {}
         \\fn foo2() callconv(.Stdcall) void {}
         \\fn foo3() callconv(.C) void {}
+        \\fn foo4() callconv(.C) void {}
         \\
     );
 }
diff --git a/lib/std/zig/render.zig b/lib/std/zig/render.zig
index e322a91dc4..069635d42e 100644
--- a/lib/std/zig/render.zig
+++ b/lib/std/zig/render.zig
@@ -1396,6 +1396,7 @@ fn renderExpression(
                     try renderToken(tree, stream, extern_export_inline_token, indent, start_col, Space.Space); // extern/export
                 } else {
                     cc_rewrite_str = ".C";
+                    fn_proto.lib_name = null;
                 }
             }