make distinct conversions addressable in VM (#24124)

fixes #24097

For `nkConv` addresses where the conversion is between 2 types that are
equal between backends, treat assignments the same as assignments to the
argument of the conversion. In the VM this seems to be in `genAsgn` and
`genAsgnPatch`, as evidenced by the special logic for `nkDerefExpr` etc.

This doesn't handle ranges after #24037 because `sameBackendType` is
used and not `sameBackendTypeIgnoreRange`. This is so this is
backportable without #24037 and another PR can be opened that implements
it for ranges and adds tests as well. We can also merge
`sameBackendTypeIgnoreRange` with `sameBackendType` since it doesn't
seem like anything that uses it would be affected (only cycle checks and
the VM), but then we still have to add tests.

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/vm/tconvaddr.nim b/tests/vm/tconvaddr.nim
new file mode 100644
index 000000000..9762a9e59
--- /dev/null
+++ b/tests/vm/tconvaddr.nim
@@ -0,0 +1,49 @@
+block: # issue #24097
+  type Foo = distinct int
+  proc foo(x: var Foo) =
+    int(x) += 1
+  proc bar(x: var int) =
+    x += 1
+  static:
+    var x = Foo(1)
+    int(x) = int(x) + 1
+    doAssert x.int == 2
+    int(x) += 1
+    doAssert x.int == 3
+    foo(x)
+    doAssert x.int == 4
+    bar(int(x)) # need vmgen flags propagated for this
+    doAssert x.int == 5
+  type Bar = object
+    x: Foo
+  static:
+    var obj = Bar(x: Foo(1))
+    int(obj.x) = int(obj.x) + 1
+    doAssert obj.x.int == 2
+    int(obj.x) += 1
+    doAssert obj.x.int == 3
+    foo(obj.x)
+    doAssert obj.x.int == 4
+    bar(int(obj.x)) # need vmgen flags propagated for this
+    doAssert obj.x.int == 5
+  static:
+    var arr = @[Foo(1)]
+    int(arr[0]) = int(arr[0]) + 1
+    doAssert arr[0].int == 2
+    int(arr[0]) += 1
+    doAssert arr[0].int == 3
+    foo(arr[0])
+    doAssert arr[0].int == 4
+    bar(int(arr[0])) # need vmgen flags propagated for this
+    doAssert arr[0].int == 5
+  proc testResult(): Foo =
+    result = Foo(1)
+    int(result) = int(result) + 1
+    doAssert result.int == 2
+    int(result) += 1
+    doAssert result.int == 3
+    foo(result)
+    doAssert result.int == 4
+    bar(int(result)) # need vmgen flags propagated for this
+    doAssert result.int == 5
+  doAssert testResult().int == 5