diff --git a/src/cmd/go/internal/modfetch/coderepo.go b/src/cmd/go/internal/modfetch/coderepo.go
index 267b763..491fe11 100644
--- a/src/cmd/go/internal/modfetch/coderepo.go
+++ b/src/cmd/go/internal/modfetch/coderepo.go
@@ -31,7 +31,7 @@
 	codeRoot string
 	// codeDir is the directory (relative to root) at which we expect to find the module.
 	// If pathMajor is non-empty and codeRoot is not the full modPath,
-	// then we look in both codeDir and codeDir+modPath
+	// then we look in both codeDir and codeDir/pathMajor[1:].
 	codeDir string
 
 	// pathMajor is the suffix of modPath that indicates its major version,
@@ -248,20 +248,25 @@
 	// exist as required by info2.Version and the module path represented by r.
 	checkGoMod := func() (*RevInfo, error) {
 		// If r.codeDir is non-empty, then the go.mod file must exist: the module
-		// author, not the module consumer, gets to decide how to carve up the repo
+		// author — not the module consumer, — gets to decide how to carve up the repo
 		// into modules.
-		if r.codeDir != "" {
-			_, _, _, err := r.findDir(info2.Version)
-			if err != nil {
-				// TODO: It would be nice to return an error like "not a module".
-				// Right now we return "missing go.mod", which is a little confusing.
-				return nil, &module.ModuleError{
-					Path: r.modPath,
-					Err: &module.InvalidVersionError{
-						Version: info2.Version,
-						Err:     notExistError(err.Error()),
-					},
-				}
+		//
+		// Conversely, if the go.mod file exists, the module author — not the module
+		// consumer — gets to determine the module's path
+		//
+		// r.findDir verifies both of these conditions. Execute it now so that
+		// r.Stat will correctly return a notExistError if the go.mod location or
+		// declared module path doesn't match.
+		_, _, _, err := r.findDir(info2.Version)
+		if err != nil {
+			// TODO: It would be nice to return an error like "not a module".
+			// Right now we return "missing go.mod", which is a little confusing.
+			return nil, &module.ModuleError{
+				Path: r.modPath,
+				Err: &module.InvalidVersionError{
+					Version: info2.Version,
+					Err:     notExistError(err.Error()),
+				},
 			}
 		}
 
@@ -571,6 +576,10 @@
 	return r.revToRev(version), nil
 }
 
+// findDir locates the directory within the repo containing the module.
+//
+// If r.pathMajor is non-empty, this can be either r.codeDir or — if a go.mod
+// file exists — r.codeDir/r.pathMajor[1:].
 func (r *codeRepo) findDir(version string) (rev, dir string, gomod []byte, err error) {
 	rev, err = r.versionToRev(version)
 	if err != nil {
diff --git a/src/cmd/go/internal/modfetch/coderepo_test.go b/src/cmd/go/internal/modfetch/coderepo_test.go
index 5fc9bc3..b5c9be5 100644
--- a/src/cmd/go/internal/modfetch/coderepo_test.go
+++ b/src/cmd/go/internal/modfetch/coderepo_test.go
@@ -105,7 +105,7 @@
 		name:    "45f53230a74ad275c7127e117ac46914c8126160",
 		short:   "45f53230a74a",
 		time:    time.Date(2018, 7, 19, 1, 21, 27, 0, time.UTC),
-		ziperr:  "missing github.com/rsc/vgotest1/go.mod and .../v2/go.mod at revision v2.0.0",
+		err:     "missing github.com/rsc/vgotest1/go.mod and .../v2/go.mod at revision v2.0.0",
 	},
 	{
 		vcs:     "git",
@@ -136,15 +136,14 @@
 		},
 	},
 	{
-		vcs:      "git",
-		path:     "github.com/rsc/vgotest1/v2",
-		rev:      "45f53230a",
-		version:  "v2.0.0",
-		name:     "45f53230a74ad275c7127e117ac46914c8126160",
-		short:    "45f53230a74a",
-		time:     time.Date(2018, 7, 19, 1, 21, 27, 0, time.UTC),
-		gomoderr: "missing github.com/rsc/vgotest1/go.mod and .../v2/go.mod at revision v2.0.0",
-		ziperr:   "missing github.com/rsc/vgotest1/go.mod and .../v2/go.mod at revision v2.0.0",
+		vcs:     "git",
+		path:    "github.com/rsc/vgotest1/v2",
+		rev:     "45f53230a",
+		version: "v2.0.0",
+		name:    "45f53230a74ad275c7127e117ac46914c8126160",
+		short:   "45f53230a74a",
+		time:    time.Date(2018, 7, 19, 1, 21, 27, 0, time.UTC),
+		err:     "missing github.com/rsc/vgotest1/go.mod and .../v2/go.mod at revision v2.0.0",
 	},
 	{
 		vcs:     "git",
@@ -154,7 +153,7 @@
 		name:    "80d85c5d4d17598a0e9055e7c175a32b415d6128",
 		short:   "80d85c5d4d17",
 		time:    time.Date(2018, 2, 19, 23, 10, 6, 0, time.UTC),
-		ziperr:  "missing github.com/rsc/vgotest1/go.mod and .../v54321/go.mod at revision 80d85c5d4d17",
+		err:     "missing github.com/rsc/vgotest1/go.mod and .../v54321/go.mod at revision 80d85c5d4d17",
 	},
 	{
 		vcs:  "git",
@@ -210,24 +209,24 @@
 		gomod:   "module \"github.com/rsc/vgotest1/v2\" // root go.mod\n",
 	},
 	{
-		vcs:      "git",
-		path:     "github.com/rsc/vgotest1/v2",
-		rev:      "v2.0.3",
-		version:  "v2.0.3",
-		name:     "f18795870fb14388a21ef3ebc1d75911c8694f31",
-		short:    "f18795870fb1",
-		time:     time.Date(2018, 2, 19, 23, 16, 4, 0, time.UTC),
-		gomoderr: "github.com/rsc/vgotest1/v2/go.mod has non-.../v2 module path \"github.com/rsc/vgotest\" at revision v2.0.3",
+		vcs:     "git",
+		path:    "github.com/rsc/vgotest1/v2",
+		rev:     "v2.0.3",
+		version: "v2.0.3",
+		name:    "f18795870fb14388a21ef3ebc1d75911c8694f31",
+		short:   "f18795870fb1",
+		time:    time.Date(2018, 2, 19, 23, 16, 4, 0, time.UTC),
+		err:     "github.com/rsc/vgotest1/v2/go.mod has non-.../v2 module path \"github.com/rsc/vgotest\" at revision v2.0.3",
 	},
 	{
-		vcs:      "git",
-		path:     "github.com/rsc/vgotest1/v2",
-		rev:      "v2.0.4",
-		version:  "v2.0.4",
-		name:     "1f863feb76bc7029b78b21c5375644838962f88d",
-		short:    "1f863feb76bc",
-		time:     time.Date(2018, 2, 20, 0, 3, 38, 0, time.UTC),
-		gomoderr: "github.com/rsc/vgotest1/go.mod and .../v2/go.mod both have .../v2 module paths at revision v2.0.4",
+		vcs:     "git",
+		path:    "github.com/rsc/vgotest1/v2",
+		rev:     "v2.0.4",
+		version: "v2.0.4",
+		name:    "1f863feb76bc7029b78b21c5375644838962f88d",
+		short:   "1f863feb76bc",
+		time:    time.Date(2018, 2, 20, 0, 3, 38, 0, time.UTC),
+		err:     "github.com/rsc/vgotest1/go.mod and .../v2/go.mod both have .../v2 module paths at revision v2.0.4",
 	},
 	{
 		vcs:     "git",
@@ -504,6 +503,7 @@
 					tt.name = remap(tt.name, m)
 					tt.short = remap(tt.short, m)
 					tt.rev = remap(tt.rev, m)
+					tt.err = remap(tt.err, m)
 					tt.gomoderr = remap(tt.gomoderr, m)
 					tt.ziperr = remap(tt.ziperr, m)
 					t.Run(strings.ReplaceAll(tt.path, "/", "_")+"/"+tt.rev, f(tt))
@@ -631,9 +631,14 @@
 		err:  "no commits",
 	},
 	{
-		vcs:     "git",
-		path:    "github.com/rsc/vgotest1",
-		version: "v0.0.0-20180219223237-a08abb797a67",
+		vcs:  "git",
+		path: "github.com/rsc/vgotest1",
+		err:  `github.com/rsc/vgotest1@v0.0.0-20180219223237-a08abb797a67: invalid version: go.mod has post-v0 module path "github.com/vgotest1/v2" at revision a08abb797a67`,
+	},
+	{
+		vcs:  "git",
+		path: "github.com/rsc/vgotest1/v2",
+		err:  `github.com/rsc/vgotest1/v2@v2.0.0-20180219223237-a08abb797a67: invalid version: github.com/rsc/vgotest1/go.mod and .../v2/go.mod both have .../v2 module paths at revision a08abb797a67`,
 	},
 	{
 		vcs:  "git",
@@ -641,6 +646,16 @@
 		err:  "github.com/rsc/vgotest1/subdir@v0.0.0-20180219223237-a08abb797a67: invalid version: missing github.com/rsc/vgotest1/subdir/go.mod at revision a08abb797a67",
 	},
 	{
+		vcs:     "git",
+		path:    "vcs-test.golang.org/git/commit-after-tag.git",
+		version: "v1.0.1-0.20190715211727-b325d8217783",
+	},
+	{
+		vcs:     "git",
+		path:    "vcs-test.golang.org/git/no-tags.git",
+		version: "v0.0.0-20190715212047-e706ba1d9f6d",
+	},
+	{
 		vcs:     "mod",
 		path:    "swtch.com/testmod",
 		version: "v1.1.1",
diff --git a/src/cmd/go/internal/modload/query_test.go b/src/cmd/go/internal/modload/query_test.go
index 10d947e..7940882 100644
--- a/src/cmd/go/internal/modload/query_test.go
+++ b/src/cmd/go/internal/modload/query_test.go
@@ -161,8 +161,11 @@
 	{path: queryRepoV2, query: "v2.6.0-pre1", vers: "v2.6.0-pre1"},
 	{path: queryRepoV2, query: "latest", vers: "v2.5.5"},
 
-	{path: queryRepoV3, query: "e0cf3de987e6", vers: "v3.0.0-20180704024501-e0cf3de987e6"},
-	{path: queryRepoV3, query: "latest", vers: "v3.0.0-20180704024501-e0cf3de987e6"},
+	// e0cf3de987e6 is the latest commit on the master branch, and it's actually
+	// v1.19.10-pre1, not anything resembling v3: attempting to query it as such
+	// should fail.
+	{path: queryRepoV3, query: "e0cf3de987e6", err: `vcs-test.golang.org/git/querytest.git/v3@v3.0.0-20180704024501-e0cf3de987e6: invalid version: go.mod has non-.../v3 module path "vcs-test.golang.org/git/querytest.git" (and .../v3/go.mod does not exist) at revision e0cf3de987e6`},
+	{path: queryRepoV3, query: "latest", err: `no matching versions for query "latest"`},
 
 	{path: emptyRepo, query: "latest", vers: "v0.0.0-20180704023549-7bb914627242"},
 	{path: emptyRepo, query: ">v0.0.0", err: `no matching versions for query ">v0.0.0"`},
@@ -182,7 +185,10 @@
 			ok, _ := path.Match(allow, m.Version)
 			return ok
 		}
+		tt := tt
 		t.Run(strings.ReplaceAll(tt.path, "/", "_")+"/"+tt.query+"/"+tt.current+"/"+allow, func(t *testing.T) {
+			t.Parallel()
+
 			info, err := Query(tt.path, tt.query, tt.current, allowed)
 			if tt.err != "" {
 				if err == nil {
diff --git a/src/cmd/go/testdata/script/mod_list_direct.txt b/src/cmd/go/testdata/script/mod_list_direct.txt
new file mode 100644
index 0000000..8f85871
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_list_direct.txt
@@ -0,0 +1,24 @@
+env GO111MODULE=on
+env GOPROXY=direct
+env GOSUMDB=off
+
+[!net] skip
+[!exec:git] skip
+
+# golang.org/issue/33099: if an import path ends in a major-version suffix,
+# ensure that 'direct' mode can resolve the package to the module.
+# For a while, (*modfetch.codeRepo).Stat was not checking for a go.mod file,
+# which would produce a hard error at the subsequent call to GoMod.
+
+go list all
+
+-- go.mod --
+module example.com
+go 1.13
+
+-- main.go --
+package main
+
+import _ "vcs-test.golang.org/git/v3pkg.git/v3"
+
+func main() {}