Add value-returning match expressions

internal/lang/sql.go

@@ -1144,6 +1144,15 @@ func exprMatches(expr Expr, match func(Expr) bool) bool {
 		return exprMatches(e.Receiver, match)
 	case IndexExpr:
 		return exprMatches(e.Receiver, match) || exprMatches(e.Index, match)
+	case MatchExpr:
+		if exprMatches(e.Value, match) {
+			return true
+		}
+		for _, matchCase := range e.Cases {
+			if exprMatches(matchCase.Value, match) {
+				return true
+			}
+		}
 	case LambdaExpr:
 		return stmtsMatch(e.Body, match)
 	}