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FIR checker: SENSELESS_(COMPARISON|NULL_IN_WHEN)

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Currently DFA does not set "definitely equal to null" for access to variables that got assigned `null`. For example, FIR should mark the following line as SENSELESS_COMPARISON due to `s = null` above.
 https://github.com/JetBrains/kotlin/blob/d1531f9cdd5852352c0133198706125dc63b6007/compiler/testData/diagnostics/tests/smartCasts/alwaysNull.fir.kt#L6

The problem is at https://github.com/JetBrains/kotlin/blob/7e9f27436a77de1c76e3705da7aa1fbe8938336b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzer.kt#L1104

For null assignment, ideally the type should be `Nothing?`. This is
addressed in a followup commit instead.
This commit is contained in:
Tianyu Geng
2021-07-20 09:46:18 -07:00
committed by teamcityserver
parent 4726dcce40
commit c7272f6986
108 changed files with 1410 additions and 1485 deletions
Download Patch File Download Diff File Expand all files Collapse all files
compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/37.fir.kt
Vendored
+2 -2
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@@ -96,7 +96,7 @@ fun case_8(x: Boolean?) {
// TESTCASE NUMBER: 9
fun case_9(x: Boolean?) {
while (x ?: return)
while (x == null)
while (<!SENSELESS_COMPARISON!>x == null<!>)
<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Boolean? & kotlin.Nothing")!>x<!>
<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Boolean? & kotlin.Boolean")!>x<!>.equals(10)
@@ -200,7 +200,7 @@ fun case_17(x: Boolean?, y: Boolean?) {
else -> if (true) if (true) if (true) if (true) if (true) x!! else x!! else x!! else x!! else x!! else x!!
}
false -> x!!
null -> if (true) if (true) if (true) if (true) if (true) x!! else x!! else x!! else x!! else x!! else x!!
<!SENSELESS_NULL_IN_WHEN!>null<!> -> if (true) if (true) if (true) if (true) if (true) x!! else x!! else x!! else x!! else x!! else x!!
} else x!! else x!! else x!! else x!! else x!!
}
break@loop