V3012 with_non_handler
with was given something that is not a Handler<E, r> value.
An error from the effect phase. sakura explain V3012 prints this explanation offline.
with was given something that is not a Handler<E, r> value. Pass a handler E { … }
expression or a function that returns one (std's handlers such as Fs.rooted(dir) and
Log.captured()); to compute a value without handling an effect, drop the with.
Wrong:
fn five() -> Int { with 5 { 1 } }Fixed:
fn five() -> Int { 5 }Wrong program
compiler/tests/ui/V3012_with_non_handler.sakura, which the compiler's ui suite runs through sakura check:
fn five() -> Int { with 5 { 1 } }sakura check --json reports this record (pretty-printed; $DIR is the fixture's directory):
{
"schema_version": "1.0",
"kind": "diagnostic",
"id": "d:6c073b9264548e20",
"code": "V3012",
"severity": "error",
"phase": "effect",
"message": "`with` needs a handler value of type `Handler<E>`, found `Int`",
"snapshot": "sha256:$SNAPSHOT",
"symbol_id": "main::V3012_with_non_handler::five",
"spans": [
{
"uri": "file://$DIR/V3012_with_non_handler.sakura",
"content_hash": "sha256:b6b87db1126e93864c1251319991b29dcf78edb208c80c00c5ed781d74dbe7f1",
"start_byte": 58,
"end_byte": 59,
"role": "primary"
}
],
"related_ids": [],
"expected": null,
"actual": {
"render": "Int"
},
"obligation": null,
"counterexample": null,
"explanation_uri": "sakura://explain/V3012",
"fixes": []
}Fixed program
compiler/tests/ui/V3012_with_non_handler.fixed.sakura, which sakura check accepts with no diagnostics:
fn five() -> Int { 5 }