httpcaddyfile: Fix expression matcher shortcut in snippets (#6288)

caddyconfig/httpcaddyfile/httptype.go

@@ -1282,19 +1282,24 @@ func matcherSetFromMatcherToken(
 	if tkn.Text == "*" {
 		// match all requests == no matchers, so nothing to do
 		return nil, true, nil
-	} else if strings.HasPrefix(tkn.Text, "/") {
-		// convenient way to specify a single path match
+	}
+
+	// convenient way to specify a single path match
+	if strings.HasPrefix(tkn.Text, "/") {
 		return caddy.ModuleMap{
 			"path": caddyconfig.JSON(caddyhttp.MatchPath{tkn.Text}, warnings),
 		}, true, nil
-	} else if strings.HasPrefix(tkn.Text, matcherPrefix) {
-		// pre-defined matcher
+	}
+
+	// pre-defined matcher
+	if strings.HasPrefix(tkn.Text, matcherPrefix) {
 		m, ok := matcherDefs[tkn.Text]
 		if !ok {
 			return nil, false, fmt.Errorf("unrecognized matcher name: %+v", tkn.Text)
 		}
 		return m, true, nil
 	}
+
 	return nil, false, nil
 }
 
@@ -1430,11 +1435,13 @@ func parseMatcherDefinitions(d *caddyfile.Dispenser, matchers map[string]caddy.M
 	if d.NextArg() {
 		if d.Token().Quoted() {
 			// since it was missing the matcher name, we insert a token
-			// in front of the expression token itself
-			err := makeMatcher("expression", []caddyfile.Token{
-				{Text: "expression", File: d.File(), Line: d.Line()},
-				d.Token(),
-			})
+			// in front of the expression token itself; we use Clone() to
+			// make the new token to keep the same the import location as
+			// the next token, if this is within a snippet or imported file.
+			// see https://github.com/caddyserver/caddy/issues/6287
+			expressionToken := d.Token().Clone()
+			expressionToken.Text = "expression"
+			err := makeMatcher("expression", []caddyfile.Token{expressionToken, d.Token()})
 			if err != nil {
 				return err
 			}