diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index bf87c4a0d103c..7a5d550997f4f 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 )
@@ -570,14 +571,23 @@ func runGet(cmd *base.Command, args []string) {
 	}
 
 	// Scan for any upgrades lost by the downgrades.
-	lost := make(map[string]string)
-	for _, m := range modload.BuildList() {
-		t := byPath[m.Path]
-		if t != nil && semver.Compare(m.Version, t.m.Version) != 0 {
-			lost[m.Path] = m.Version
+	var lostUpgrades []*query
+	var versionByPath map[string]string
+	if len(down) > 0 {
+		versionByPath = make(map[string]string)
+		for _, m := range modload.BuildList() {
+			versionByPath[m.Path] = m.Version
 		}
+		for _, q := range byPath {
+			if v, ok := versionByPath[q.m.Path]; q.m.Version != "none" && (!ok || semver.Compare(v, q.m.Version) != 0) {
+				lostUpgrades = append(lostUpgrades, q)
+			}
+		}
+		sort.Slice(lostUpgrades, func(i, j int) bool {
+			return lostUpgrades[i].m.Path < lostUpgrades[j].m.Path
+		})
 	}
-	if len(lost) > 0 {
+	if len(lostUpgrades) > 0 {
 		desc := func(m module.Version) string {
 			s := m.Path + "@" + m.Version
 			t := byPath[m.Path]
@@ -590,19 +600,17 @@ func runGet(cmd *base.Command, args []string) {
 		for _, d := range down {
 			downByPath[d.Path] = d
 		}
+
 		var buf strings.Builder
 		fmt.Fprintf(&buf, "go get: inconsistent versions:")
 		reqs := modload.Reqs()
-		for _, q := range queries {
-			if lost[q.m.Path] == "" {
-				continue
-			}
+		for _, q := range lostUpgrades {
 			// We lost q because its build list requires a newer version of something in down.
 			// Figure out exactly what.
 			// Repeatedly constructing the build list is inefficient
 			// if there are MANY command-line arguments,
 			// but at least all the necessary requirement lists are cached at this point.
-			list, err := mvs.BuildList(q.m, reqs)
+			list, err := buildListForLostUpgrade(q.m, reqs)
 			if err != nil {
 				base.Fatalf("go: %v", err)
 			}
@@ -618,7 +626,12 @@ func runGet(cmd *base.Command, args []string) {
 			if sep != "," {
 				// We have no idea why this happened.
 				// At least report the problem.
-				fmt.Fprintf(&buf, " ended up at %v unexpectedly (please report at golang.org/issue/new)", lost[q.m.Path])
+				if v := versionByPath[q.m.Path]; v == "" {
+					fmt.Fprintf(&buf, " removed unexpectedly")
+				} else {
+					fmt.Fprintf(&buf, " ended up at %s unexpectedly", v)
+				}
+				fmt.Fprintf(&buf, " (please report at golang.org/issue/new)")
 			}
 		}
 		base.Fatalf("%v", buf.String())
@@ -894,3 +907,29 @@ func (u *upgrader) Upgrade(m module.Version) (module.Version, error) {
 
 	return module.Version{Path: m.Path, Version: info.Version}, nil
 }
+
+// buildListForLostUpgrade returns the build list for the module graph
+// rooted at lost. Unlike mvs.BuildList, the target module (lost) is not
+// treated specially. The returned build list may contain a newer version
+// of lost.
+//
+// buildListForLostUpgrade is used after a downgrade has removed a module
+// requested at a specific version. This helps us understand the requirements
+// implied by each downgrade.
+func buildListForLostUpgrade(lost module.Version, reqs mvs.Reqs) ([]module.Version, error) {
+	return mvs.BuildList(lostUpgradeRoot, &lostUpgradeReqs{Reqs: reqs, lost: lost})
+}
+
+var lostUpgradeRoot = module.Version{Path: "lost-upgrade-root", Version: ""}
+
+type lostUpgradeReqs struct {
+	mvs.Reqs
+	lost module.Version
+}
+
+func (r *lostUpgradeReqs) Required(mod module.Version) ([]module.Version, error) {
+	if mod == lostUpgradeRoot {
+		return []module.Version{r.lost}, nil
+	}
+	return r.Reqs.Required(mod)
+}
diff --git a/src/cmd/go/internal/mvs/mvs.go b/src/cmd/go/internal/mvs/mvs.go
index d1c3d8c08ad43..90f8f269b571f 100644
--- a/src/cmd/go/internal/mvs/mvs.go
+++ b/src/cmd/go/internal/mvs/mvs.go
@@ -121,9 +121,6 @@ func BuildList(target module.Version, reqs Reqs) ([]module.Version, error) {
 func buildList(target module.Version, reqs Reqs, upgrade func(module.Version) module.Version) ([]module.Version, error) {
 	// Explore work graph in parallel in case reqs.Required
 	// does high-latency network operations.
-	var work par.Work
-	work.Add(target)
-
 	type modGraphNode struct {
 		m        module.Version
 		required []module.Version
@@ -137,6 +134,7 @@ func buildList(target module.Version, reqs Reqs, upgrade func(module.Version) mo
 		haveErr  int32
 	)
 
+	var work par.Work
 	work.Add(target)
 	work.Do(10, func(item interface{}) {
 		m := item.(module.Version)
@@ -217,6 +215,11 @@ func buildList(target module.Version, reqs Reqs, upgrade func(module.Version) mo
 	// Construct the list by traversing the graph again, replacing older
 	// modules with required minimum versions.
 	if v := min[target.Path]; v != target.Version {
+		// TODO(jayconrod): there is a special case in modload.mvsReqs.Max
+		// that prevents us from selecting a newer version of a module
+		// when the module has no version. This may only be the case for target.
+		// Should we always panic when target has a version?
+		// See golang.org/issue/31491, golang.org/issue/29773.
 		panic(fmt.Sprintf("mistake: chose version %q instead of target %+v", v, target)) // TODO: Don't panic.
 	}
 
diff --git a/src/cmd/go/testdata/mod/example.com_newcycle_a_v1.0.0.txt b/src/cmd/go/testdata/mod/example.com_newcycle_a_v1.0.0.txt
new file mode 100644
index 0000000000000..829065df9fb96
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_newcycle_a_v1.0.0.txt
@@ -0,0 +1,10 @@
+example.com/newcycle/a v1.0.0
+
+Transitively requires v1.0.1 of itself via example.com/newcycle/b
+
+-- .mod --
+module example.com/newcycle/a
+
+require example.com/newcycle/b v1.0.0
+-- .info --
+{"Version":"v1.0.0"}
diff --git a/src/cmd/go/testdata/mod/example.com_newcycle_a_v1.0.1.txt b/src/cmd/go/testdata/mod/example.com_newcycle_a_v1.0.1.txt
new file mode 100644
index 0000000000000..a03f4b49fd5ec
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_newcycle_a_v1.0.1.txt
@@ -0,0 +1,10 @@
+example.com/newcycle/a v1.0.1
+
+Transitively requires itself via example.com/newcycle/b
+
+-- .mod --
+module example.com/newcycle/a
+
+require example.com/newcycle/b v1.0.0
+-- .info --
+{"Version":"v1.0.1"}
diff --git a/src/cmd/go/testdata/mod/example.com_newcycle_b_v1.0.0.txt b/src/cmd/go/testdata/mod/example.com_newcycle_b_v1.0.0.txt
new file mode 100644
index 0000000000000..ff9e1f5ea5fa6
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_newcycle_b_v1.0.0.txt
@@ -0,0 +1,8 @@
+example.com/newcycle/b v1.0.0
+
+-- .mod --
+module example.com/newcycle/b
+
+require example.com/newcycle/a v1.0.1
+-- .info --
+{"Version":"v1.0.0"}
diff --git a/src/cmd/go/testdata/script/mod_get_newcycle.txt b/src/cmd/go/testdata/script/mod_get_newcycle.txt
new file mode 100644
index 0000000000000..9616863383dae
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_get_newcycle.txt
@@ -0,0 +1,14 @@
+env GO111MODULE=on
+
+# Download modules to avoid stderr chatter
+go mod download example.com/newcycle/a@v1.0.0
+go mod download example.com/newcycle/a@v1.0.1
+go mod download example.com/newcycle/b@v1.0.0
+
+go mod init m
+! go get example.com/newcycle/a@v1.0.0
+cmp stderr stderr-expected
+
+-- stderr-expected --
+go get: inconsistent versions:
+	example.com/newcycle/a@v1.0.0 requires example.com/newcycle/a@v1.0.1 (not example.com/newcycle/a@v1.0.0)