FIR checker: SENSELESS_(COMPARISON|NULL_IN_WHEN)

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
@@ -17,7 +17,7 @@ fun case_1(x: ClassWithCustomEquals) {
// TESTCASE NUMBER: 2
fun case_2(x: ClassWithCustomEquals) {
if (x == null) {
if (<!SENSELESS_COMPARISON!>x == null<!>) {
<!DEBUG_INFO_EXPRESSION_TYPE("ClassWithCustomEquals & kotlin.Nothing")!>x<!>
<!DEBUG_INFO_EXPRESSION_TYPE("ClassWithCustomEquals & kotlin.Nothing")!>x<!>.inv()
}
@@ -75,7 +75,7 @@ fun case_6(x: ClassWithCustomEquals) {
// TESTCASE NUMBER: 7
fun case_7(x: ClassWithCustomEquals) {
if ((x != null) == false) {
if ((<!SENSELESS_COMPARISON!>x != null<!>) == false) {
<!DEBUG_INFO_EXPRESSION_TYPE("ClassWithCustomEquals & kotlin.Nothing")!>x<!>
<!DEBUG_INFO_EXPRESSION_TYPE("ClassWithCustomEquals & kotlin.Nothing")!>x<!>.inv()
}