diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index ee8ac8a176..f4a92686a5 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -528,7 +528,7 @@ func runGet(cmd *base.Command, args []string) {
 					// current directory, even if it is not tho module root.
 					continue
 				}
-				if strings.HasPrefix(p.Error.Err, "no Go files") && modload.ModuleInfo(p.ImportPath) != nil {
+				if strings.Contains(p.Error.Err, "cannot find module providing") && modload.ModuleInfo(p.ImportPath) != nil {
 					// Explicitly-requested module, but it doesn't contain a package at the
 					// module root.
 					continue
@@ -551,13 +551,6 @@ func runGet(cmd *base.Command, args []string) {
 // If forceModulePath is set, getQuery must interpret path
 // as a module path.
 func getQuery(path, vers string, forceModulePath bool) (module.Version, error) {
-	if path == modload.Target.Path {
-		if vers != "" {
-			return module.Version{}, fmt.Errorf("cannot update main module to explicit version")
-		}
-		return modload.Target, nil
-	}
-
 	if vers == "" {
 		vers = "latest"
 	}
@@ -569,36 +562,14 @@ func getQuery(path, vers string, forceModulePath bool) (module.Version, error) {
 		return module.Version{Path: path, Version: info.Version}, nil
 	}
 
-	// Even if the query fails, if the path is (or must be) a real module, then report the query error.
-	if forceModulePath || *getM || isModulePath(path) {
+	// Even if the query fails, if the path must be a real module, then report the query error.
+	if forceModulePath || *getM {
 		return module.Version{}, err
 	}
 
-	// Otherwise, interpret the package path as an import
-	// and determine what module that import would address
-	// if found in the current source code.
-	// Then apply the version to that module.
-	m, _, err := modload.Import(path)
-	if e, ok := err.(*modload.ImportMissingError); ok && e.Module.Path != "" {
-		m = e.Module
-	} else if err != nil {
-		return module.Version{}, err
-	}
-	if m.Path == "" {
-		return module.Version{}, fmt.Errorf("package %q is not in a module", path)
-	}
-	info, err = modload.Query(m.Path, vers, modload.Allowed)
-	if err != nil {
-		return module.Version{}, err
-	}
-	return module.Version{Path: m.Path, Version: info.Version}, nil
-}
-
-// isModulePath reports whether path names an actual module,
-// defined as one with an accessible latest version.
-func isModulePath(path string) bool {
-	_, err := modload.Query(path, "latest", modload.Allowed)
-	return err == nil
+	// Otherwise, try a package path.
+	m, _, err := modload.QueryPackage(path, vers, modload.Allowed)
+	return m, err
 }
 
 // An upgrader adapts an underlying mvs.Reqs to apply an
diff --git a/src/cmd/go/internal/modload/import.go b/src/cmd/go/internal/modload/import.go
index fc845c2974..3b954f18fe 100644
--- a/src/cmd/go/internal/modload/import.go
+++ b/src/cmd/go/internal/modload/import.go
@@ -10,7 +10,6 @@ import (
 	"fmt"
 	"go/build"
 	"os"
-	pathpkg "path"
 	"path/filepath"
 	"strings"
 
@@ -124,24 +123,6 @@ func Import(path string) (m module.Version, dir string, err error) {
 		return module.Version{}, "", errors.New(buf.String())
 	}
 
-	// Special case: if the path matches a module path,
-	// and we haven't found code in any module on the build list
-	// (since we haven't returned yet),
-	// force the use of the current module instead of
-	// looking for an alternate one.
-	// This helps "go get golang.org/x/net" even though
-	// there is no code in x/net.
-	for _, m := range buildList {
-		if m.Path == path {
-			root, isLocal, err := fetch(m)
-			if err != nil {
-				return module.Version{}, "", err
-			}
-			dir, _ := dirInModule(path, m.Path, root, isLocal)
-			return m, dir, nil
-		}
-	}
-
 	// Not on build list.
 
 	// Look up module containing the package, for addition to the build list.
@@ -150,43 +131,11 @@ func Import(path string) (m module.Version, dir string, err error) {
 		return module.Version{}, "", fmt.Errorf("import lookup disabled by -mod=%s", cfg.BuildMod)
 	}
 
-	for p := path; p != "."; p = pathpkg.Dir(p) {
-		// We can't upgrade the main module.
-		// Note that this loop does consider upgrading other modules on the build list.
-		// If that's too aggressive we can skip all paths already on the build list,
-		// not just Target.Path, but for now let's try being aggressive.
-		if p == Target.Path {
-			// Can't move to a new version of main module.
-			continue
-		}
-
-		info, err := Query(p, "latest", Allowed)
-		if err != nil {
-			continue
-		}
-		m := module.Version{Path: p, Version: info.Version}
-		root, isLocal, err := fetch(m)
-		if err != nil {
-			continue
-		}
-		_, ok := dirInModule(path, m.Path, root, isLocal)
-		if ok {
-			return module.Version{}, "", &ImportMissingError{ImportPath: path, Module: m}
-		}
-
-		// Special case matching the one above:
-		// if m.Path matches path, assume adding it to the build list
-		// will either add the right code or the right code doesn't exist.
-		if m.Path == path {
-			return module.Version{}, "", &ImportMissingError{ImportPath: path, Module: m}
-		}
+	m, _, err = QueryPackage(path, "latest", Allowed)
+	if err != nil {
+		return module.Version{}, "", &ImportMissingError{ImportPath: path}
 	}
-
-	// Did not resolve import to any module.
-	// TODO(rsc): It would be nice to return a specific error encountered
-	// during the loop above if possible, but it's not clear how to pick
-	// out the right one.
-	return module.Version{}, "", &ImportMissingError{ImportPath: path}
+	return m, "", &ImportMissingError{ImportPath: path, Module: m}
 }
 
 // maybeInModule reports whether, syntactically,
diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index c69e49acd9..bd3141865c 100644
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -9,6 +9,7 @@ import (
 	"cmd/go/internal/module"
 	"cmd/go/internal/semver"
 	"fmt"
+	pathpkg "path"
 	"strings"
 )
 
@@ -29,6 +30,8 @@ import (
 //
 // If the allowed function is non-nil, Query excludes any versions for which allowed returns false.
 //
+// If path is the path of the main module and the query is "latest",
+// Query returns Target.Version as the version.
 func Query(path, query string, allowed func(module.Version) bool) (*modfetch.RevInfo, error) {
 	if allowed == nil {
 		allowed = func(module.Version) bool { return true }
@@ -117,6 +120,16 @@ func Query(path, query string, allowed func(module.Version) bool) (*modfetch.Rev
 		return info, nil
 	}
 
+	if path == Target.Path {
+		if query != "latest" {
+			return nil, fmt.Errorf("can't query specific version (%q) for the main module (%s)", query, path)
+		}
+		if !allowed(Target) {
+			return nil, fmt.Errorf("internal error: main module version is not allowed")
+		}
+		return &modfetch.RevInfo{Version: Target.Version}, nil
+	}
+
 	// Load versions and execute query.
 	repo, err := modfetch.Lookup(path)
 	if err != nil {
@@ -187,3 +200,44 @@ func isSemverPrefix(v string) bool {
 func matchSemverPrefix(p, v string) bool {
 	return len(v) > len(p) && v[len(p)] == '.' && v[:len(p)] == p
 }
+
+// QueryPackage looks up a revision of a module containing path.
+//
+// If multiple modules with revisions matching the query provide the requested
+// package, QueryPackage picks the one with the longest module path.
+//
+// If the path is in the the main module and the query is "latest",
+// QueryPackage returns Target as the version.
+func QueryPackage(path, query string, allowed func(module.Version) bool) (module.Version, *modfetch.RevInfo, error) {
+	if _, ok := dirInModule(path, Target.Path, ModRoot, true); ok {
+		if query != "latest" {
+			return module.Version{}, nil, fmt.Errorf("can't query specific version (%q) for package %s in the main module (%s)", query, path, Target.Path)
+		}
+		if !allowed(Target) {
+			return module.Version{}, nil, fmt.Errorf("internal error: package %s is in the main module (%s), but version is not allowed", path, Target.Path)
+		}
+		return Target, &modfetch.RevInfo{Version: Target.Version}, nil
+	}
+
+	finalErr := errMissing
+	for p := path; p != "."; p = pathpkg.Dir(p) {
+		info, err := Query(p, query, allowed)
+		if err != nil {
+			if finalErr == errMissing {
+				finalErr = err
+			}
+			continue
+		}
+		m := module.Version{Path: p, Version: info.Version}
+		root, isLocal, err := fetch(m)
+		if err != nil {
+			return module.Version{}, nil, err
+		}
+		_, ok := dirInModule(path, m.Path, root, isLocal)
+		if ok {
+			return m, info, nil
+		}
+	}
+
+	return module.Version{}, nil, finalErr
+}
diff --git a/src/cmd/go/testdata/mod/example.com_join_subpkg_v1.0.0.txt b/src/cmd/go/testdata/mod/example.com_join_subpkg_v1.0.0.txt
new file mode 100644
index 0000000000..1ecfa0b6de
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_join_subpkg_v1.0.0.txt
@@ -0,0 +1,9 @@
+Written by hand.
+Test case for package moved into a parent module.
+
+-- .mod --
+module example.com/join/subpkg
+-- .info --
+{"Version": "v1.0.0"}
+-- x.go --
+package subpkg
diff --git a/src/cmd/go/testdata/mod/example.com_join_subpkg_v1.1.0.txt b/src/cmd/go/testdata/mod/example.com_join_subpkg_v1.1.0.txt
new file mode 100644
index 0000000000..9eb823adb7
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_join_subpkg_v1.1.0.txt
@@ -0,0 +1,9 @@
+Written by hand.
+Test case for package moved into a parent module.
+
+-- .mod --
+module example.com/join/subpkg
+
+require example.com/join v1.1.0
+-- .info --
+{"Version": "v1.1.0"}
diff --git a/src/cmd/go/testdata/mod/example.com_join_v1.0.0.txt b/src/cmd/go/testdata/mod/example.com_join_v1.0.0.txt
new file mode 100644
index 0000000000..84c68b13b6
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_join_v1.0.0.txt
@@ -0,0 +1,7 @@
+Written by hand.
+Test case for package moved into a parent module.
+
+-- .mod --
+module example.com/join
+-- .info --
+{"Version": "v1.0.0"}
diff --git a/src/cmd/go/testdata/mod/example.com_join_v1.1.0.txt b/src/cmd/go/testdata/mod/example.com_join_v1.1.0.txt
new file mode 100644
index 0000000000..5f92036d9e
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_join_v1.1.0.txt
@@ -0,0 +1,9 @@
+Written by hand.
+Test case for package moved into a parent module.
+
+-- .mod --
+module example.com/join
+-- .info --
+{"Version": "v1.1.0"}
+-- subpkg/x.go --
+package subpkg
diff --git a/src/cmd/go/testdata/mod/example.com_split_subpkg_v1.1.0.txt b/src/cmd/go/testdata/mod/example.com_split_subpkg_v1.1.0.txt
new file mode 100644
index 0000000000..b197b66398
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_split_subpkg_v1.1.0.txt
@@ -0,0 +1,11 @@
+Written by hand.
+Test case for getting a package that has been moved to a different module.
+
+-- .mod --
+module example.com/split/subpkg
+
+require example.com/split v1.1.0
+-- .info --
+{"Version": "v1.1.0"}
+-- x.go --
+package subpkg
diff --git a/src/cmd/go/testdata/mod/example.com_split_v1.0.0.txt b/src/cmd/go/testdata/mod/example.com_split_v1.0.0.txt
new file mode 100644
index 0000000000..b706e590d9
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_split_v1.0.0.txt
@@ -0,0 +1,9 @@
+Written by hand.
+Test case for getting a package that has been moved to a different module.
+
+-- .mod --
+module example.com/split
+-- .info --
+{"Version": "v1.0.0"}
+-- subpkg/x.go --
+package subpkg
diff --git a/src/cmd/go/testdata/mod/example.com_split_v1.1.0.txt b/src/cmd/go/testdata/mod/example.com_split_v1.1.0.txt
new file mode 100644
index 0000000000..d38971f9b6
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_split_v1.1.0.txt
@@ -0,0 +1,9 @@
+Written by hand.
+Test case for getting a package that has been moved to a different module.
+
+-- .mod --
+module example.com/split
+
+require example.com/split/subpkg v1.1.0
+-- .info --
+{"Version": "v1.1.0"}
diff --git a/src/cmd/go/testdata/script/mod_bad_domain.txt b/src/cmd/go/testdata/script/mod_bad_domain.txt
index 829c88517e..c9fd044cdc 100644
--- a/src/cmd/go/testdata/script/mod_bad_domain.txt
+++ b/src/cmd/go/testdata/script/mod_bad_domain.txt
@@ -2,9 +2,9 @@ env GO111MODULE=on
 
 # explicit get should report errors about bad names
 ! go get appengine
-stderr 'cannot find module providing package appengine'
+stderr 'malformed module path "appengine": missing dot in first path element'
 ! go get x/y.z
-stderr 'cannot find module providing package x/y.z'
+stderr 'malformed module path "x/y.z": missing dot in first path element'
 
 # build should report all unsatisfied imports,
 # but should be more definitive about non-module import paths
diff --git a/src/cmd/go/testdata/script/mod_get_indirect.txt b/src/cmd/go/testdata/script/mod_get_indirect.txt
index f567e97c6c..3ae5833834 100644
--- a/src/cmd/go/testdata/script/mod_get_indirect.txt
+++ b/src/cmd/go/testdata/script/mod_get_indirect.txt
@@ -15,7 +15,7 @@ grep 'golang.org/x/text [v0-9a-f\.-]+ // indirect' go.mod
 # TODO(bcmills): This doesn't seem correct. Fix is in the next change.
 cp $WORK/tmp/usetext.go x.go
 go list -e
-grep 'golang.org/x/text [v0-9a-f\.-]+$' go.mod
+grep 'golang.org/x/text [v0-9a-f\.-]+ // indirect' go.mod
 
 # indirect tag should be removed upon seeing direct import.
 cp $WORK/tmp/uselang.go x.go
diff --git a/src/cmd/go/testdata/script/mod_get_local.txt b/src/cmd/go/testdata/script/mod_get_local.txt
index 5d2b6cd356..4edda993f1 100644
--- a/src/cmd/go/testdata/script/mod_get_local.txt
+++ b/src/cmd/go/testdata/script/mod_get_local.txt
@@ -35,13 +35,13 @@ grep 'rsc.io/quote.*v1.5.2' go.mod
 grep 'golang.org/x/text.*v0.3.0' go.mod
 cp go.mod go.mod.dotpkg
 
-# BUG: 'go get -u -d' with an explicit package in a local-only package fails.
-# TODO: Determine the correct behavior.
+# 'go get -u -d' with an explicit package in the main module updates
+# all dependencies of the main module.
+# TODO: Determine whether that behavior is a bug.
 # (https://golang.org/issue/26902)
 cp go.mod.orig go.mod
-! go get -u -d local/uselang
-stderr 'missing dot in first path element'
-cmp go.mod go.mod.orig
+go get -u -d local/uselang
+cmp go.mod go.mod.dotpkg
 
 
 -- go.mod --
diff --git a/src/cmd/go/testdata/script/mod_get_moved.txt b/src/cmd/go/testdata/script/mod_get_moved.txt
new file mode 100644
index 0000000000..be91449155
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_get_moved.txt
@@ -0,0 +1,37 @@
+env GO111MODULE=on
+
+# A 'go get' that worked at a previous version should continue to work at that version,
+# even if the package was subsequently moved into a submodule.
+go mod init example.com/foo
+go get -d example.com/split/subpkg@v1.0.0
+go list -m all
+stdout 'example.com/split v1.0.0'
+
+# A 'go get' that simultaneously upgrades away conflicting package defitions is not ambiguous.
+go get example.com/split/subpkg@v1.1.0
+
+# A 'go get' without an upgrade should find the package.
+rm go.mod
+go mod init example.com/foo
+go get -d example.com/split/subpkg
+go list -m all
+stdout 'example.com/split/subpkg v1.1.0'
+
+
+# A 'go get' that worked at a previous version should continue to work at that version,
+# even if the package was subsequently moved into a parent module.
+rm go.mod
+go mod init example.com/foo
+go get -d example.com/join/subpkg@v1.0.0
+go list -m all
+stdout 'example.com/join/subpkg v1.0.0'
+
+# A 'go get' that simultaneously upgrades away conflicting package definitions is not ambiguous.
+go get example.com/join/subpkg@v1.1.0
+
+# A 'go get' without an upgrade should find the package.
+rm go.mod
+go mod init example.com/foo
+go get -d example.com/join/subpkg@v1.1.0
+go list -m all
+stdout 'example.com/join v1.1.0'