E07406: returning block is not required as there is no 'lhs' variable to assign it to

What went wrong

You've added a returning block (<- ...) to a control structure, but you're not using it in an assignment. The return value would be lost.

Worked examples

Compilable examples demonstrating this error and the correct fix:

• ek9 -q 782 (When does a switch need a returning block in EK9?)

How to fix it

1. Capture the result in an assignment
2. Or remove returning block for statement form

Common causes

• Statement with return that's not captured
• Refactoring left orphaned return

See also

• E07406: statement with orphaned return (this error)
• E07405: expression without return

Examples

Every example is compiled by the EK9 compiler: the first fails exactly as captioned, the others fix it.

Fails with E07406: returning block is not required as there is no 'lhs' variable to assign it to

#!ek9
defines module error.e07406.bad

  defines function

    describe()
      -> word as String
      <- rtn as String: String()

      //Nothing receives the switch's value
      switch word
        <- text as String: String()
        case "ToCheck"
          rtn: "Jackpot"
        default
          rtn: "Nothing"

Fixed: Remove the returning declaration from a switch statement

#!ek9
defines module error.e07406.good

  defines function

    describe()
      -> word as String
      <- rtn as String: String()

      //A switch statement: no returning variable
      switch word
        case "ToCheck"
          rtn: "Jackpot"
        default
          rtn: "Nothing"

Questions and answers

These Q&A entries show E07406 and its fix:

• Q782: When does a switch need a returning block in EK9?