Tianyu Geng
c7272f6986
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.
20 lines
457 B
Kotlin
Vendored
20 lines
457 B
Kotlin
Vendored
fun x(): Boolean { return true }
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public fun foo(qq: String?): Int {
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var q = qq
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while(true) {
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q!!.length
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var r = q
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do {
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var p = r
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do {
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// p = r, r = q and q is not null
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p.length
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} while (!x())
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} while (<!SENSELESS_COMPARISON!>r == null<!>) // r = q and q is not null
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if (!x()) break
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}
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// Smart cast is possible
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return q.length
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}
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