Skip to Content

Filter the sidebar/

Start

Introduction Getting started Install Build modes

Reference

Diagnostics JSON output

Error codes M0000 error M0001 syntax error M0002 undefined name M0003 no such field or method M0004 declared and not used M0005 imported and not used M0006 type mismatch M0007 mismatched types M0008 wrong number of return values M0009 wrong number of arguments M0010 missing return M0011 package not found M0012 assignment count mismatch M0013 no new variables M0014 does not implement interface M0015 redeclared M0016 invalid operation M0017 bad command line M0018 link error M0019 internal compiler error M0020 runtime panic M0021 fatal runtime error M0022 test failed M0023 import cycle M0024 name not exported M0025 not supported by marmot M0026 type argument does not satisfy constraint M0027 cannot infer type argument M0028 shadowed variable M0029 unknown struct field M0100 vet finding M0101 lint finding M0102 modernize suggestion M0103 not formatted M0104 gopls finding M0105 known vulnerability M0106 go.mod not tidy M0107 cross build failure M0108 unreachable function M0109 switch misses cases M0110 possible nil dereference M0111 heap allocation

cgo Agent setup

Inside

Design Benchmarks Support Support matrix FAQ

DiagnosticsError codes

M0108 unreachable function

No path from main or a test reaches the function, so it is dead code.

Last updated Nov 13, 2026View as Markdown Agent setup

The fix

Remove it, or use it.

See also all error codes and marmot explain.

M0107 cross build failure

The module builds for this platform but not for another one it is checked for: a file with a build tag or a platform name is missing a function or uses one that does not exist there.

M0109 switch misses cases

A switch on an enum-like type (a defined integer or string type with package level constants of that type) does not handle every constant, or a type switch on a sealed interface (one with an unexported method, so only its package implements it) does not handle every implementation, and there is no default clause.

On this page

Was this page helpful?

Report an issue Open issues