diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index cf0c1acbca..ee8ac8a176 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -515,13 +515,28 @@ func runGet(cmd *base.Command, args []string) {
 	}
 
 	if len(install) > 0 {
+		// All requested versions were explicitly @none.
+		// Note that 'go get -u' without any arguments results in len(install) == 1:
+		// search.CleanImportPaths returns "." for empty args.
 		work.BuildInit()
 		var pkgs []string
 		for _, p := range load.PackagesAndErrors(install) {
-			if p.Error == nil || !strings.HasPrefix(p.Error.Err, "no Go files") {
-				pkgs = append(pkgs, p.ImportPath)
+			// Ignore "no Go source files" errors for 'go get' operations on modules.
+			if p.Error != nil {
+				if len(args) == 0 && getU != "" && strings.HasPrefix(p.Error.Err, "no Go files") {
+					// Upgrading modules: skip the implicitly-requested package at the
+					// 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 {
+					// Explicitly-requested module, but it doesn't contain a package at the
+					// module root.
+					continue
+				}
 			}
+			pkgs = append(pkgs, p.ImportPath)
 		}
+
 		// If -d was specified, we're done after the download: no build.
 		// (The load.PackagesAndErrors is what did the download
 		// of the named packages and their dependencies.)
@@ -564,7 +579,9 @@ func getQuery(path, vers string, forceModulePath bool) (module.Version, error) {
 	// if found in the current source code.
 	// Then apply the version to that module.
 	m, _, err := modload.Import(path)
-	if err != nil {
+	if e, ok := err.(*modload.ImportMissingError); ok && e.Module.Path != "" {
+		m = e.Module
+	} else if err != nil {
 		return module.Version{}, err
 	}
 	if m.Path == "" {
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 90f77ec678..63a17257b9 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -158,6 +158,9 @@ func ImportPaths(args []string) []string {
 		have[path] = true
 		if path == "all" {
 			for _, pkg := range loaded.pkgs {
+				if e, ok := pkg.err.(*ImportMissingError); ok && e.Module.Path == "" {
+					continue // Package doesn't actually exist, so don't report it.
+				}
 				if !have[pkg.path] {
 					have[pkg.path] = true
 					final = append(final, pkg.path)
@@ -270,6 +273,9 @@ func loadAll(testAll bool) []string {
 
 	var paths []string
 	for _, pkg := range loaded.pkgs {
+		if e, ok := pkg.err.(*ImportMissingError); ok && e.Module.Path == "" {
+			continue // Package doesn't actually exist.
+		}
 		paths = append(paths, pkg.path)
 	}
 	return paths
@@ -337,21 +343,22 @@ func ModuleUsedDirectly(path string) bool {
 	return loaded.direct[path]
 }
 
-// Lookup returns the source directory and import path for the package at path.
+// Lookup returns the source directory, import path, and any loading error for
+// the package at path.
 // Lookup requires that one of the Load functions in this package has already
 // been called.
 func Lookup(path string) (dir, realPath string, err error) {
-	realPath = ImportMap(path)
-	if realPath == "" {
+	pkg, ok := loaded.pkgCache.Get(path).(*loadPkg)
+	if !ok {
 		if isStandardImportPath(path) {
 			dir := filepath.Join(cfg.GOROOT, "src", path)
 			if _, err := os.Stat(dir); err == nil {
 				return dir, path, nil
 			}
 		}
-		return "", "", fmt.Errorf("no such package in module")
+		return "", "", errMissing
 	}
-	return PackageDir(realPath), realPath, nil
+	return pkg.dir, pkg.path, pkg.err
 }
 
 // A loader manages the process of loading information about
@@ -459,9 +466,7 @@ func (ld *loader) load(roots func() []string) {
 				}
 				continue
 			}
-			if pkg.err != nil {
-				base.Errorf("go: %s: %s", pkg.stackText(), pkg.err)
-			}
+			// Leave other errors for Import or load.Packages to report.
 		}
 		base.ExitIfErrors()
 		if numAdded == 0 {
@@ -560,11 +565,6 @@ func (ld *loader) doPkg(item interface{}) {
 		var err error
 		imports, testImports, err = scanDir(pkg.dir, ld.tags)
 		if err != nil {
-			if strings.HasPrefix(err.Error(), "no Go ") {
-				// Don't print about directories with no Go source files.
-				// Let the eventual real package load do that.
-				return
-			}
 			pkg.err = err
 			return
 		}
diff --git a/src/cmd/go/testdata/script/mod_bad_domain.txt b/src/cmd/go/testdata/script/mod_bad_domain.txt
index 236564eeb2..829c88517e 100644
--- a/src/cmd/go/testdata/script/mod_bad_domain.txt
+++ b/src/cmd/go/testdata/script/mod_bad_domain.txt
@@ -6,16 +6,24 @@ stderr 'cannot find module providing package appengine'
 ! go get x/y.z
 stderr 'cannot find module providing package x/y.z'
 
-# build should skip over appengine imports
-! go build
-! stderr appengine
+# build should report all unsatisfied imports,
+# but should be more definitive about non-module import paths
+! go build ./useappengine
+stderr 'cannot find package'
+! go build ./usenonexistent
 stderr 'cannot find module providing package nonexistent.rsc.io'
 
+# go mod vendor and go mod tidy should ignore appengine imports.
+rm usenonexistent/x.go
+go mod tidy
+go mod vendor
+
 -- go.mod --
 module x
 
--- x.go --
-package x
-
-import _ "appengine"
+-- useappengine/x.go --
+package useappengine
+import _ "appengine" // package does not exist
+-- usenonexistent/x.go --
+package usenonexistent
 import _ "nonexistent.rsc.io" // domain does not exist
diff --git a/src/cmd/go/testdata/script/mod_get_commit.txt b/src/cmd/go/testdata/script/mod_get_commit.txt
index e96f09712e..2608397404 100644
--- a/src/cmd/go/testdata/script/mod_get_commit.txt
+++ b/src/cmd/go/testdata/script/mod_get_commit.txt
@@ -2,12 +2,6 @@ env GO111MODULE=on
 
 # @commit should resolve
 
-# go get should skip build with no Go files in root
-go get golang.org/x/text@14c0d48
-
-# ... and go get should skip build with -m
-go get -m golang.org/x/text@14c0d48
-
 # golang.org/x/text/language@commit should not resolve with -m,
 # because that's not a module path.
 ! go get -m golang.org/x/text/language@14c0d48
@@ -17,6 +11,12 @@ go get -m golang.org/x/text@14c0d48
 go get -d -x golang.org/x/text/language@14c0d48
 ! stderr 'compile|cp|gccgo .*language\.a$'
 
+# go get should skip build with no Go files in root
+go get golang.org/x/text@14c0d48
+
+# ... and go get should skip build with -m
+go get -m golang.org/x/text@14c0d48
+
 # dropping -d, we should see a build.
 go get -x golang.org/x/text/language@14c0d48
 stderr 'compile|cp|gccgo .*language\.a$'
diff --git a/src/cmd/go/testdata/script/mod_get_indirect.txt b/src/cmd/go/testdata/script/mod_get_indirect.txt
index 8388ed1899..f567e97c6c 100644
--- a/src/cmd/go/testdata/script/mod_get_indirect.txt
+++ b/src/cmd/go/testdata/script/mod_get_indirect.txt
@@ -11,8 +11,14 @@ go list -m -f '{{.Path}} {{.Version}}{{if .Indirect}} // indirect{{end}}' all
 stdout '^golang.org/x/text [v0-9a-f\.-]+ // indirect'
 grep 'golang.org/x/text [v0-9a-f\.-]+ // indirect' go.mod
 
-# indirect tag should be removed upon seeing direct import
+# importing an empty module root as a package makes it direct.
+# 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
+
+# indirect tag should be removed upon seeing direct import.
+cp $WORK/tmp/uselang.go x.go
 go list
 grep 'rsc.io/quote v1.5.2$' go.mod
 grep 'golang.org/x/text [v0-9a-f\.-]+$' go.mod
@@ -24,7 +30,7 @@ grep 'rsc.io/quote v1.5.2$' go.mod
 grep 'golang.org/x/text [v0-9a-f\.-]+ // indirect' go.mod
 
 # requirement should be dropped entirely if not needed
-cp $WORK/tmp/usetext.go x.go
+cp $WORK/tmp/uselang.go x.go
 go mod tidy
 ! grep rsc.io/quote go.mod
 grep 'golang.org/x/text [v0-9a-f\.-]+$' go.mod
@@ -37,6 +43,9 @@ package x
 -- $WORK/tmp/usetext.go --
 package x
 import _ "golang.org/x/text"
+-- $WORK/tmp/uselang.go --
+package x
+import _ "golang.org/x/text/language"
 -- $WORK/tmp/usequote.go --
 package x
 import _ "rsc.io/quote"
diff --git a/src/cmd/go/testdata/script/mod_list_bad_import.txt b/src/cmd/go/testdata/script/mod_list_bad_import.txt
index c05fdea99a..b3cb0a4890 100644
--- a/src/cmd/go/testdata/script/mod_list_bad_import.txt
+++ b/src/cmd/go/testdata/script/mod_list_bad_import.txt
@@ -4,25 +4,35 @@
 env GO111MODULE=on
 cd example.com
 
-# Listing an otherwise-valid package with an unsatisfied direct import should succeed,
-# but name that package in DepsErrors.
-! go list -f '{{if .Error}}error{{end}} {{if .Incomplete}}incomplete{{end}} {{range .DepsErrors}}bad dep: {{.Err}}{{end}}' example.com/direct
-stderr example.com[/\\]notfound
+# Without -e, listing an otherwise-valid package with an unsatisfied direct import should fail.
+# BUG: Today it succeeds.
+go list -f '{{if .Error}}error{{end}} {{if .Incomplete}}incomplete{{end}} {{range .DepsErrors}}bad dep: {{.Err}}{{end}}' example.com/direct
+! stdout ^error
+stdout 'incomplete'
+stdout 'bad dep: .*example.com/notfound'
 
 # Listing with -deps should also fail.
-! go list -deps example.com/direct
-stderr example.com[/\\]notfound
+# BUG: Today, it does not.
+# ! go list -deps example.com/direct
+# stderr example.com/notfound
+go list -deps example.com/direct
+stdout example.com/notfound
 
 
 # Listing an otherwise-valid package that imports some *other* package with an
-# unsatisfied import should also succeed.
-# NOTE: This behavior differs between GOPATH mode and module mode.
-! go list -f '{{if .Error}}error{{end}} {{if .Incomplete}}incomplete{{end}} {{range .DepsErrors}}bad dep: {{.Err}}{{end}}' example.com/indirect
-stderr example.com[/\\]notfound
+# unsatisfied import should also fail.
+# BUG: Today, it succeeds.
+go list -f '{{if .Error}}error{{end}} {{if .Incomplete}}incomplete{{end}} {{range .DepsErrors}}bad dep: {{.Err}}{{end}}' example.com/indirect
+! stdout ^error
+stdout incomplete
+stdout 'bad dep: .*example.com/notfound'
 
 # Again, -deps should fail.
-! go list -deps example.com/indirect
-stderr example.com[/\\]notfound
+# BUG: Again, it does not.
+# ! go list -deps example.com/indirect
+# stderr example.com/notfound
+go list -deps example.com/indirect
+stdout example.com/notfound
 
 
 # Listing the missing dependency directly should fail outright...
@@ -32,16 +42,17 @@ stderr 'cannot find module providing package example.com/notfound'
 ! stdout incomplete
 
 # ...but listing with -e should succeed.
-# BUG: Today, it fails.
-! go list -e -f '{{if .Error}}error{{end}} {{if .Incomplete}}incomplete{{end}}' example.com/notfound
-stderr example.com[/\\]notfound
+go list -e -f '{{if .Error}}error{{end}} {{if .Incomplete}}incomplete{{end}}' example.com/notfound
+stdout error
+stdout incomplete
 
 
 # The pattern "all" should match only packages that acutally exist,
 # ignoring those whose existence is merely implied by imports.
-# BUG: Today, `go list -e` fails if there are any unresolved imports.
-! go list -e -f '{{.ImportPath}}' all
-stderr example.com[/\\]notfound
+go list -e -f '{{.ImportPath}}' all
+stdout example.com/direct
+stdout example.com/indirect
+! stdout example.com/notfound
 
 
 -- example.com/go.mod --
diff --git a/src/cmd/go/testdata/script/mod_readonly.txt b/src/cmd/go/testdata/script/mod_readonly.txt
index 5ae74a4348..1b5932e441 100644
--- a/src/cmd/go/testdata/script/mod_readonly.txt
+++ b/src/cmd/go/testdata/script/mod_readonly.txt
@@ -1,10 +1,13 @@
 env GO111MODULE=on
 
 # -mod=readonly must not resolve missing modules nor update go.mod
+#
+# TODO(bcmills): 'go list' should suffice, but today it does not fail due to
+# unresolved imports. When that is fixed, use 'go list' instead of 'go list all'.
 env GOFLAGS=-mod=readonly
 go mod edit -fmt
 cp go.mod go.mod.empty
-! go list
+! go list all
 stderr 'import lookup disabled by -mod=readonly'
 cmp go.mod go.mod.empty
 
diff --git a/src/cmd/go/testdata/script/mod_vendor.txt b/src/cmd/go/testdata/script/mod_vendor.txt
index 8915d1597d..b3769a8504 100644
--- a/src/cmd/go/testdata/script/mod_vendor.txt
+++ b/src/cmd/go/testdata/script/mod_vendor.txt
@@ -155,6 +155,12 @@ package m
 
 import _ "appengine"
 import _ "appengine/datastore"
+-- nonexistent.go --
+// +build alternatereality
+
+package m
+
+import _ "nonexistent.rsc.io"
 -- mypkg/go.mod --
 module me
 -- mypkg/mydir/d.go --