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
@@ -87,7 +87,7 @@ fun <T> T?.case_4() {
// TESTCASE NUMBER: 5
fun <T> T?.case_5() {
if (this is Interface1) {
if (this != null) {
if (<!SENSELESS_COMPARISON!>this != null<!>) {
<!DEBUG_INFO_EXPRESSION_TYPE("T? & Interface1 & T?!!")!>this<!>
<!DEBUG_INFO_EXPRESSION_TYPE("T? & Interface1 & T?!!")!>this<!>.equals(null)
this.propT
@@ -319,7 +319,7 @@ fun <T> T.case_8() {
// TESTCASE NUMBER: 9
fun <T : Number> T.case_9() {
if (this != null) {
if (<!SENSELESS_COMPARISON!>this != null<!>) {
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>.equals(null)
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>.propT
@@ -566,7 +566,7 @@ fun <T> T.case_12() where T : Number?, T: Interface1? {
* ISSUES: KT-28785
*/
fun <T> T.case_13() where T : Out<*>?, T: Comparable<T?> {
if (this != null) {
if (<!SENSELESS_COMPARISON!>this != null<!>) {
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>.equals(null)
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>.propT
@@ -3493,7 +3493,7 @@ fun <T> T.case_56() where T : Number?, T: Interface1? {
* ISSUES: KT-28785
*/
fun <T> T.case_57() where T : Out<*>?, T: Comparable<T?> {
if (this != null) {
if (<!SENSELESS_COMPARISON!>this != null<!>) {
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>.equals(null)
<!DEBUG_INFO_EXPRESSION_TYPE("T")!>this<!>.propT
@@ -3798,7 +3798,7 @@ fun <T> T.case_61() where T : InterfaceWithTypeParameter1<T>?, T: Case61_3<T>?,
// TESTCASE NUMBER: 62
fun Nothing?.case_62() {
if (this != null) {
if (<!SENSELESS_COMPARISON!>this != null<!>) {
<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing? & kotlin.Nothing")!>this<!>
<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing? & kotlin.Nothing")!>this<!>.hashCode()
@@ -3817,7 +3817,7 @@ fun Nothing?.case_62() {
// TESTCASE NUMBER: 63
fun Nothing.case_63() {
if (this != null) {
if (<!SENSELESS_COMPARISON!>this != null<!>) {
<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing")!>this<!>
<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing")!>this<!>.hashCode()