While snooping around in the file cache I noticed a crash dump from a non-test binary: the v0.12.0 release binary, in fact. The report is

{
   "AtTime" : "2023-06-01T16:57:35.701388-04:00",
   "Description" : "no metadata for file:///Users/adonovan/w/xtools/aaa/aaa.go",
   "File" : "/Users/adonovan/go/pkg/mod/golang.org/x/tools/gopls@v0.12.0/internal/lsp/source/hover.go",
   "Key" : "/Users/adonovan/go/pkg/mod/golang.org/x/tools/gopls@v0.12.0/internal/lsp/source/hover.go:272",
   "Line" : 272,
   ...
}

The stack (which I've omitted) provides no useful information that isn't deducible from the line number above. Here's the source:

		// For package names, we simply link to their imported package.
		if pkgName, ok := obj.(*types.PkgName); ok {
			linkName = pkgName.Name()
			linkPath = pkgName.Imported().Path()
			impID := linkMeta.DepsByPkgPath[PackagePath(pkgName.Imported().Path())]
			linkMeta = snapshot.Metadata(impID)
			if linkMeta == nil {
				return protocol.Range{}, nil, bug.Errorf("no metadata for %s", declPGF.URI) // <--- here
			}
		} else {

Sadly I no longer have (or remember) the contents of aaa.go, a scratch file I used for a quick experiment.

Also: although gopls stats decodes bug reports from the same executable, it's surprisingly laborious to enumerate and decode all the bug reports from all versions $GOPLSCACHE/gopls/*/*/*-bug, since these (binary) files contain the (hex) names of other files: a sort of binary symlink. (I ended up just grepping for the shibboleth "AtTime".) It would be nice if there was a simple command to print all bug reports in the GOPLSCACHE, including those from other gopls binaries (a best-effort decoding, of course, since the format may evolve).