Currently, this is staged in as `_forget`,
as part of SE-390. It can only be used on
`self` for a move-only type within a consuming
method or accessor. There are other rules, see
Sema for the details.
A `forget self` really just consumes self and
performs memberwise destruction of its data.
Thus, the current expansion of this statement
just reuses what we inject into the end of a
deinit.
Parsing of `forget` is "contextual".
By contextual I mean that we do lookahead to
the next token and see if it's identifier-like.
If so, then we parse it as the `forget` statement.
Otherwise, we parse it as though "forget" is an
identifier as part of some expression.
This way, we won't introduce a source break for
people who wrote code that calls a forget
function.
This should make it seamless to change it from
`_forget` to `forget` in the future.
resolves rdar://105795731
Provide ASTWalker with a customization point to specify whether to
check macro arguments (which are type checked but never emitted), the
macro expansion (which is the result of applying the macro and is
actually emitted into the source), or both. Provide answers for the
~115 different ASTWalker visitors throughout the code base.
Fixes rdar://104042945, which concerns checking of effects in
macro arguments---which we shouldn't do.
This fixes an issue if the range ends with a string literal that contains the IDE inspection target. In that case the end of the range will point to the start of the string literal but the IDE inspection target is inside the string literal and thus after the range’s end.
Previous implementation blindly took the first solution
and tried to diagnose, but that's not a safe assumption.
It's possible that among the solution-fix pairs, one
of `noncopyableTy`'s within the fix differs from the
others. Things probably can go wrong because the solution
doesn't correspond to that type.
Also, in that case we'd be emitting a diagnostic that
may not make any sense. In such cases, now we decline
to emit a diagnostic.
Thanks Pavel for catching this.
Since values of generic type are currently assumed to always
support copying, we need to prevent move-only types from
being substituted for generic type parameters.
This approach leans on a `_Copyable` marker protocol to which
all generic type parameters implicitly must conform.
A few other changes in this initial implementation:
- Now every concrete type that can conform to Copyable will do so. This fixes issues with conforming to a protocol that requires Copyable.
- Narrowly ban writing a concrete type `[T]` when `T` is move-only.
Introduce SingleValueStmtExpr, which allows the
embedding of a statement in an expression context.
This then allows us to parse and type-check `if`
and `switch` statements as expressions, gated
behind the `IfSwitchExpression` experimental
feature for now. In the future,
SingleValueStmtExpr could also be used for e.g
`do` expressions.
For now, only single expression branches are
supported for producing a value from an
`if`/`switch` expression, and each branch is
type-checked independently. A multi-statement
branch may only appear if it ends with a `throw`,
and it may not `break`, `continue`, or `return`.
The placement of `if`/`switch` expressions is also
currently limited by a syntactic use diagnostic.
Currently they're only allowed in bindings,
assignments, throws, and returns. But this could
be lifted in the future if desired.
associated failure diagnostic.
This constraint fix is unused now that MacroExpansionExpr always has an
argument list, and goes through the AddMissingArguments constraint fix for
this error.
If we don't have an associated TypeRepr for a
contextual type in the constraint system, dump the
ASTNode that it's for instead.
Before:
```
Contextual Type: $T2
```
After:
```
Contextual Type: $T2 at DeclRef@/Users/hamish/src/swift-test-arena/swift-test-arena/main.swift:1493:21
```
