// RUN: %target-sil-opt %s -yield-once-check -o /dev/null -verify
//
// SIL-level tests for yield-once diagnostics emitted for yield-once coroutines.
// Note that the yield-once check runs on all functions with yield_once
// qualifier in their type, regardless of whether or not they are
// accessors of a property. In fact, currently it is not possible to parse
// a property with _read and _modify accessors from a SIL source.

sil_stage raw

import Builtin
import Swift

sil @testNoYield : $@yield_once @convention(thin) () -> @yields Int {
bb0:
%2 = tuple ()
return %2 : $() // expected-error {{accessor must yield before returning}}
}

struct TestYield {
  var flag : Builtin.Int1
  var stored: Int64
}

sil @testMultipleYields : $@yield_once @convention(thin) (TestYield) -> @yields Int64 {
bb0(%0 : $TestYield):
%1 = struct_extract %0 : $TestYield, #TestYield.flag
cond_br %1, bb1, bb3

bb1:
%5 = struct_extract %0 : $TestYield, #TestYield.stored
yield %5 : $Int64, resume bb2, unwind bb6 // expected-note {{previous yield was here}}

bb2:
br bb4

bb3:
br bb4

bb4:
%9 = struct_extract %0 : $TestYield, #TestYield.stored
yield %9 : $Int64, resume bb5, unwind bb7 // expected-error {{accessor must not yield more than once}}

bb5:
%11 = tuple ()
return %11 : $()

bb6:
br bb8

bb7:
br bb8

bb8:
unwind
}

sil @testPartialReturnWithoutYield : $@yield_once @convention(thin) (TestYield) -> @yields Int64 {
bb0(%0 : $TestYield):
%1 = struct_extract %0 : $TestYield, #TestYield.flag
cond_br %1, bb1, bb3					   // expected-note {{missing yield when the condition is false}}

bb1:
%5 = struct_extract %0 : $TestYield, #TestYield.stored
yield %5 : $Int64, resume bb2, unwind bb5

bb2:
br bb4

bb3:
br bb4

bb4:
%21 = tuple ()
return %21 : $()                          // expected-error {{accessor must yield on all paths before returning}}

bb5:
unwind
}

sil @testExplicitReturns : $@yield_once @convention(thin) (TestYield) -> @yields Int64 {
bb0(%0 : $TestYield):
%2 = struct_extract %0 : $TestYield, #TestYield.stored
%3 = integer_literal $Builtin.Int64, 0
%4 = struct_extract %2 : $Int64, #Int64._value
%5 = builtin "cmp_slt_Int64"(%3 : $Builtin.Int64, %4 : $Builtin.Int64) : $Builtin.Int1
%6 = struct $Bool (%5 : $Builtin.Int1)
%7 = struct_extract %6 : $Bool, #Bool._value
cond_br %7, bb1, bb2						// expected-note {{missing yield when the condition is true}}

bb1:
br bb4

bb2:
%10 = struct_extract %0 : $TestYield, #TestYield.stored
yield %10 : $Int64, resume bb3, unwind bb5

bb3:
br bb4

bb4:
%13 = tuple ()
return %13 : $()                            // expected-error {{accessor must yield on all paths before returning}}

bb5:
unwind
}