}

	if e.newMissingVersion != "" {
		return fmt.Sprintf("package %s provided by %s at latest version %s but not at required version %s", e.Path, e.Module.Path, e.Module.Version, e.newMissingVersion)
	}

	return fmt.Sprintf("missing module for import: %s@%s provides %s", e.Module.Path, e.Module.Version, e.Path)
}

func (e *ImportMissingError) Unwrap() error {
	return e.QueryErr
}

func (e *ImportMissingError) ImportPath() string {

	})
	return min, nil
}

// UpgradeAll returns a build list for the target module
// in which every module is upgraded to its latest version.
func UpgradeAll(target module.Version, reqs UpgradeReqs) ([]module.Version, error) {
	return buildList([]module.Version{target}, reqs, func(m module.Version) (module.Version, error) {
		if m.Path == target.Path {
			return target, nil
		}

		return reqs.Upgrade(m)

	"cmd/go/internal/modload"
	"cmd/go/internal/toolchain"

	"golang.org/x/mod/module"
)

var cmdDownload = &base.Command{
	UsageLine: "go mod download [-x] [-json] [-reuse=old.json] [modules]",
	Short:     "download modules to local cache",
	Long: `
Download downloads the named modules, which can be module patterns selecting
dependencies of the main module or module queries of the form path@version.

// It also returns the modroot of the module providing the replacement if
// one was found.
func resolveReplacement(m module.Version) module.Version {
	if r := Replacement(m); r.Path != "" {
		return r
	}
	return m
}

func toReplaceMap(replacements []*modfile.Replace) map[module.Version]module.Version {
	replaceMap := make(map[module.Version]module.Version, len(replacements))
	for _, r := range replacements {

     *           (a module existing only in test output, not in main output) should be uncommon.</li>
     *     </ul>
     *   </li>
     *   <li>Otherwise (test output contains no module information), then:
     *     <ul>
     *       <li>If the main output is on the module-path, place the test output
     *           on a {@code --patch-module} option.</li>

     *
     * <p><b>Algorithm:</b>
     * If the given path is a directory, then there is a choice:
     * </p>
     * <ul>
     *   <li><b>Package hierarchy:</b> if a {@code module-info.class} file is found at the root,
     *       then builds a singleton map with the module name declared in that descriptor.</li>

// In this example, "rsc.io/qr" is both a module path and an import path.
// But "rsc.io/qr/gf256" is only an import path, not a module path:
// it names an importable package, but not a module.
//
// As a special case to incorporate code written before modules were
// introduced, if a path p resolves using the pre-module "go get" lookup
// to the root of a source code repository without a go.mod file,

 * or another kind of path.
 *
 * <p>One path type is handled in a special way: unlike other options,
 * the paths specified in a {@code --patch-module} Java option is effective only for a specified module.
 * This type is created by calls to {@link #patchModule(String)} and a new instance must be created for
 * every module to patch.</p>
 *

	// selectedRoot records the edited version (possibly "none") for each module
	// path that would be a root in the edited requirements.
	var selectedRoot map[string]string // module path → edited version
	if rootPruning == pruned {
		selectedRoot = maps.Clone(rs.maxRootVersion)
	} else {
		// In a module without graph pruning, modules that provide packages imported
		// by the main module may either be explicit roots or implicit transitive

# resolved to a module.
! go install ./needmod/needmod.go
stderr 'needmod[/\\]needmod.go:10:2: no required module provides package example.com/version: go.mod file not found in current directory or any parent directory; see ''go help modules''$'

# 'go run' should fail if a package argument must be resolved to a module.
! go run example.com/printversion