diff --git a/src/cmd/go/internal/get/vcs.go b/src/cmd/go/internal/get/vcs.go
index d73d1146f0..2e4d6388cf 100644
--- a/src/cmd/go/internal/get/vcs.go
+++ b/src/cmd/go/internal/get/vcs.go
@@ -21,6 +21,7 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
+	"cmd/go/internal/load"
 	"cmd/go/internal/web"
 )
 
@@ -661,7 +662,7 @@ func RepoRootForImportPath(importPath string, mod ModuleMode, security web.Secur
 	if err == errUnknownSite {
 		rr, err = repoRootForImportDynamic(importPath, mod, security)
 		if err != nil {
-			err = fmt.Errorf("unrecognized import path %q: %v", importPath, err)
+			err = load.ImportErrorf(importPath, "unrecognized import path %q: %v", importPath, err)
 		}
 	}
 	if err != nil {
@@ -676,7 +677,7 @@ func RepoRootForImportPath(importPath string, mod ModuleMode, security web.Secur
 	if err == nil && strings.Contains(importPath, "...") && strings.Contains(rr.Root, "...") {
 		// Do not allow wildcards in the repo root.
 		rr = nil
-		err = fmt.Errorf("cannot expand ... in %q", importPath)
+		err = load.ImportErrorf(importPath, "cannot expand ... in %q", importPath)
 	}
 	return rr, err
 }
@@ -700,7 +701,7 @@ func repoRootFromVCSPaths(importPath string, security web.SecurityMode, vcsPaths
 		m := srv.regexp.FindStringSubmatch(importPath)
 		if m == nil {
 			if srv.prefix != "" {
-				return nil, fmt.Errorf("invalid %s import path %q", srv.prefix, importPath)
+				return nil, load.ImportErrorf(importPath, "invalid %s import path %q", srv.prefix, importPath)
 			}
 			continue
 		}
diff --git a/src/cmd/go/internal/modfetch/coderepo.go b/src/cmd/go/internal/modfetch/coderepo.go
index 849e8c7ca1..de757ecd27 100644
--- a/src/cmd/go/internal/modfetch/coderepo.go
+++ b/src/cmd/go/internal/modfetch/coderepo.go
@@ -359,7 +359,7 @@ func (r *codeRepo) convert(info *codehost.RevInfo, statVers string) (*RevInfo, e
 				Path: r.modPath,
 				Err: &module.InvalidVersionError{
 					Version: info2.Version,
-					Err:     notExistError(err.Error()),
+					Err:     notExistError{err: err},
 				},
 			}
 		}
diff --git a/src/cmd/go/internal/modfetch/repo.go b/src/cmd/go/internal/modfetch/repo.go
index 4273da0317..f03bdd8d03 100644
--- a/src/cmd/go/internal/modfetch/repo.go
+++ b/src/cmd/go/internal/modfetch/repo.go
@@ -250,9 +250,9 @@ func (lookupDisabledError) Error() string {
 var errLookupDisabled error = lookupDisabledError{}
 
 var (
-	errProxyOff       = notExistError("module lookup disabled by GOPROXY=off")
-	errNoproxy  error = notExistError("disabled by GOPRIVATE/GONOPROXY")
-	errUseProxy error = notExistError("path does not match GOPRIVATE/GONOPROXY")
+	errProxyOff       = notExistErrorf("module lookup disabled by GOPROXY=off")
+	errNoproxy  error = notExistErrorf("disabled by GOPRIVATE/GONOPROXY")
+	errUseProxy error = notExistErrorf("path does not match GOPRIVATE/GONOPROXY")
 )
 
 func lookupDirect(path string) (Repo, error) {
@@ -264,7 +264,7 @@ func lookupDirect(path string) (Repo, error) {
 	rr, err := get.RepoRootForImportPath(path, get.PreferMod, security)
 	if err != nil {
 		// We don't know where to find code for a module with this path.
-		return nil, notExistError(err.Error())
+		return nil, notExistError{err: err}
 	}
 
 	if rr.VCS == "mod" {
@@ -408,11 +408,22 @@ func (l *loggingRepo) Zip(dst io.Writer, version string) error {
 }
 
 // A notExistError is like os.ErrNotExist, but with a custom message
-type notExistError string
+type notExistError struct {
+	err error
+}
+
+func notExistErrorf(format string, args ...interface{}) error {
+	return notExistError{fmt.Errorf(format, args...)}
+}
 
 func (e notExistError) Error() string {
-	return string(e)
+	return e.err.Error()
 }
+
 func (notExistError) Is(target error) bool {
 	return target == os.ErrNotExist
 }
+
+func (e notExistError) Unwrap() error {
+	return e.err
+}
diff --git a/src/cmd/go/internal/modload/import.go b/src/cmd/go/internal/modload/import.go
index a01ef62d55..dc0fc3c4d0 100644
--- a/src/cmd/go/internal/modload/import.go
+++ b/src/cmd/go/internal/modload/import.go
@@ -43,6 +43,9 @@ func (e *ImportMissingError) Error() string {
 		if str.HasPathPrefix(e.Path, "cmd") {
 			return fmt.Sprintf("package %s is not in GOROOT (%s)", e.Path, filepath.Join(cfg.GOROOT, "src", e.Path))
 		}
+		if i := load.ImportPathError(nil); errors.As(e.QueryErr, &i) {
+			return fmt.Sprintf("cannot find module: %v", e.QueryErr)
+		}
 		if e.QueryErr != nil {
 			return fmt.Sprintf("cannot find module providing package %s: %v", e.Path, e.QueryErr)
 		}
diff --git a/src/go/build/build_test.go b/src/go/build/build_test.go
index 8045487174..b5c813b3e2 100644
--- a/src/go/build/build_test.go
+++ b/src/go/build/build_test.go
@@ -515,14 +515,21 @@ func TestMissingImportErrorRepetition(t *testing.T) {
 	os.Setenv("GO111MODULE", "on")
 	defer os.Setenv("GOPROXY", os.Getenv("GOPROXY"))
 	os.Setenv("GOPROXY", "off")
+	defer os.Setenv("GONOPROXY", os.Getenv("GONOPROXY"))
+	os.Setenv("GONOPROXY", "none")
 
 	ctxt := Default
 	ctxt.WorkingDir = tmp
 
 	pkgPath := "example.com/hello"
-	if _, err = ctxt.Import(pkgPath, tmp, FindOnly); err == nil {
+	_, err = ctxt.Import(pkgPath, tmp, FindOnly)
+	if err == nil {
 		t.Fatal("unexpected success")
-	} else if n := strings.Count(err.Error(), pkgPath); n != 1 {
+	}
+	// Don't count the package path with a URL like https://...?go-get=1.
+	// See golang.org/issue/35986.
+	errStr := strings.ReplaceAll(err.Error(), "://"+pkgPath+"?go-get=1", "://...?go-get=1")
+	if n := strings.Count(errStr, pkgPath); n != 1 {
 		t.Fatalf("package path %q appears in error %d times; should appear once\nerror: %v", pkgPath, n, err)
 	}
 }