Otherwise `debug/stepping/enum.kt` starts failing as soon as we advance
default language version to 1.9, because with the introduction of enum
entries, enum's `<clinit>` now invokes LambdaMetafactory which invokes
its own bundled version of ASM located in
`jdk.internal.org.objectweb.asm`, so we end up stepping over a lot of
internal ASM code.
`jdk.internal.*` is also excluded by default in the debugger settings in
IntelliJ, so users will not observe this issue in practice.
This will allow to keep backward compatiblity for deprecated
kotlinOptions DSL for already existing compiler arguments, but add a new
one only into compilerOptions DSL.
^KT-53108 In Progress
If you care about direction, then you also care about labels.
3 out of 6 places that use `traverse` are incorrect, by the way.
Node order does not correspond to scoping boundaries.
UncaughtExceptionPath label out of a finally block matches every label
that is not handled by another edge, and a labeled edge from the middle
of a finally block aborts the jump and so should merge all available
data.
Instead, rely on the variable assignment analyzer to properly restrict
smart casts. This makes error messages more consistent, but otherwise
should have no effect.
Also fix graphs for enums with specialized entries - since we don't
create property subgraphs for FirEnumEntry, there is no body to insert
AnonymousObjectEnterNode, AnonymousObjectExitNode, and
AnonymousObjectExpressionExitNode into.
They are only used in one place that can just as well use kinds.
Especially considering that "the one place" used them incorrectly and
would not attach local functions in property accessors as subgraphs.
function enter -> default 1 -> default 2 -> rest of function
\----------^ \----------^
This probably has no effect (in non-stupid code, at least), but it makes
graph construction more architecturally correct (now value parameters'
subgraphs get attached to a node).
Interpretation: a graph A is a subgraph of B if information available at
nodes of A depends on the paths taken in B. For example, local classes
are subgraphs of a graph in which they are declared, and members of
those classes are subgraphs of the local class itself - because these
members can reference captured values.
Consequences:
* if graph G is a subgraph of node N, then G is a subgraph of N's
owner;
* `ControlFlowAnalysisDiagnosticComponent` will only visit root graphs;
* `graph.traverse` will ignore subgraph boundaries, as if all subgraphs
are inlined into one huge root graph;
* if a control flow checker needs information from a declaration to
which a graph is attached, it must look at subgraphs explicitly.
For example, consider the `callsInPlace` checker. When a function
has a `callsInPlace` contract and a local declaration, the checker must
visit that local declaration to ensure it does not capture the allegedly
called-in-place argument - hence `graph.traverse` will look at the
nodes. However, the local declaration can also be a function with its
own `callsInPlace` contracts, so the checker should also run for it in
isolation. If that sounds quadratic, that's because unfortunately it is.
* `do { continue } while (x)`: block exit is dead, condition is not;
* `try { a?.incomplete() } catch (e) { x }`: when the call is completed
and found to return `Nothing`, the safe call exit node is still live
because `a` could still be null;
* `f(a@{ g { return@a } }, x)`: if call to `g` is not completed, there
should not be a dead data flow edge from the lambda to `f` because
there's no such thing as a dead data flow edge (DeadForward is CF+DF).
The receiver of the provideDelegate call is the same FirExpression as
the delegate itself, so there's only one copy of the nodes in the first
place; trying to remove subgraphs completely detaches objects inside it
from the parent graph, which is not great for checkers.
Note that currently if provideDelegate is not selected, there will be a
stray FunctionCallExit node in the control flow graph. This commit *does
not change that*. It has been there for a while. Don't @ me. I'll try to
fix that. No promises.
Anton Bannykh