"error: redefinition of label 'blk'" when translating C macro

[judofyr]

Zig Version

0.10.0-dev.4249+11dce7894

Steps to Reproduce

I don't have a fully reproducible case yet. This is happening when attempting to translate part of the PostgreSQL 15 headers.

Expected Behavior

No compilation error.

Actual Behavior

I'm getting the following error:

$ zig build test
zig-cache/o/1e6cc7956eea0b29702f59fbeba95335/cimport.zig:15598:13: error: redefinition of label 'blk'
        _ = blk: {
            ^~~
zig-cache/o/1e6cc7956eea0b29702f59fbeba95335/cimport.zig:15597:12: note: previous definition here
    return blk: {
           ^~~
src/postgresql/parser.zig:4:16: error: C import failed: AnalysisFail
const parser = @cImport({
               ^~~~~~~~
referenced by:
    test.can use parser: src/postgresql/parser.zig:26:5
    remaining reference traces hidden; use '-freference-trace' to see all reference traces

error: test...

Inspecting file at e6cc7956eea0b29702f59fbeba95335/cimport.zig:15598 I see that the following was attempted to be translated:

pub inline fn LSN_FORMAT_ARGS(lsn: anytype) uint32 {
    return blk: {
        _ = blk: {
            _ = AssertVariableIsOfTypeMacro(lsn, XLogRecPtr);
            break :blk @import("std").zig.c_translation.cast(uint32, lsn >> @as(c_int, 32));
        };
        break :blk @import("std").zig.c_translation.cast(uint32, lsn);
    };
}

The actual macro looks like this:

/*
 * Handy macro for printing XLogRecPtr in conventional format, e.g.,
 *
 * printf("%X/%X", LSN_FORMAT_ARGS(lsn));
 */
#define LSN_FORMAT_ARGS(lsn) (AssertVariableIsOfTypeMacro((lsn), XLogRecPtr), (uint32) ((lsn) >> 32)), ((uint32) (lsn))

Hopefully someone else is able to make a smaller reproducible test.