importas: fix duplication detection when aliases use regular expressi…

…on replacement pattern (#3869)

pkg/golinters/importas.go

@@ -3,6 +3,7 @@ package golinters
 import (
  "fmt"
  "strconv"
+ "strings"
 
  "github.com/julz/importas" //nolint:misspell
  "golang.org/x/tools/go/analysis"
@@ -50,7 +51,8 @@ func NewImportAs(settings *config.ImportAsSettings) *goanalysis.Linter {
  uniqPackages[a.Pkg] = a
  }
 
- if v, ok := uniqAliases[a.Alias]; ok {
+ // skip the duplication check when the alias is a regular expression replacement pattern (ie. contains `$`).
+ if v, ok := uniqAliases[a.Alias]; ok && !strings.Contains(a.Alias, "$") {
  lintCtx.Log.Errorf("invalid configuration, multiple packages with the same alias: alias=%s packages=[%s,%s]", a.Alias, a.Pkg, v.Pkg)
  } else {
  uniqAliases[a.Alias] = a