From 7e43a0d9efb7abd5506c71dacd2097500fc2c26a Mon Sep 17 00:00:00 2001
From: Dmitriy Novozhilov <dmitriy.novozhilov@jetbrains.com>
Date: Tue, 27 Aug 2019 11:22:51 +0300
Subject: [PATCH] [FIR] Add boolean constant folding for DFA

---
 .../kotlin/fir/resolve/dfa/Condition.kt       |   2 +
 .../resolve/dfa/FirDataFlowAnalyzerImpl.kt    |  48 +-
 .../smartcasts/equalsToBoolean.cfg.dot        | 440 ++++++++++++++++++
 .../resolve/smartcasts/equalsToBoolean.kt     |  68 +++
 .../resolve/smartcasts/equalsToBoolean.txt    |  96 ++++
 .../fir/FirCfgBuildingTestGenerated.java      |   5 +
 6 files changed, 646 insertions(+), 13 deletions(-)
 create mode 100644 compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.cfg.dot
 create mode 100644 compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.kt
 create mode 100644 compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.txt

diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/Condition.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/Condition.kt
index 6d9f660e07a..4f95cdbd803 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/Condition.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/Condition.kt
@@ -19,6 +19,8 @@ enum class ConditionValue(val token: String) {
     }
 }
 
+fun Boolean.toConditionValue(): ConditionValue = if (this) ConditionValue.True else ConditionValue.False
+
 enum class ConditionOperator(val token: String) {
     Eq("=="), NotEq("!=");
 
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzerImpl.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzerImpl.kt
index defa391e7ad..4eed06bdb1d 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzerImpl.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzerImpl.kt
@@ -184,9 +184,9 @@ class FirDataFlowAnalyzerImpl(transformer: FirBodyResolveTransformer) : FirDataF
                     when {
                         leftConst?.kind == IrConstKind.Null -> processEqNull(node, rightOperand, operation)
                         rightConst?.kind == IrConstKind.Null -> processEqNull(node, leftOperand, operation)
+                        leftConst != null -> processEqWithConst(node, rightOperand, leftConst, operation)
+                        rightConst != null -> processEqWithConst(node, leftOperand, rightConst, operation)
                         operation != FirOperation.EQ && operation != FirOperation.IDENTITY -> return
-                        leftConst != null -> processEqWithConst(node, rightOperand)
-                        rightConst != null -> processEqWithConst(node, leftOperand)
                         else -> processEq(node, leftOperand, rightOperand, operation)
                     }
                 }
@@ -196,19 +196,41 @@ class FirDataFlowAnalyzerImpl(transformer: FirBodyResolveTransformer) : FirDataF
         }
     }
 
-    private fun processEqWithConst(node: OperatorCallNode, operand: FirExpression) {
-        val operandVariables = getRealVariablesForSafeCallChain(operand).takeIf { it.isNotEmpty() } ?: return
+    private fun processEqWithConst(node: OperatorCallNode, operand: FirExpression, const: FirConstExpression<*>, operation: FirOperation) {
+        val isEq = when (operation) {
+            FirOperation.EQ, FirOperation.IDENTITY -> true
+            FirOperation.NOT_EQ, FirOperation.NOT_IDENTITY -> false
+            else -> return
+        }
+
         val expressionVariable = getVariable(node.fir)
         var flow = node.flow
-        operandVariables.forEach { operandVariable ->
-            flow = flow.addNotApprovedFact(
-                expressionVariable, UnapprovedFirDataFlowInfo(
-                    eq(True),
-                    operandVariable,
-                    FirDataFlowInfo(setOf(session.builtinTypes.anyType.coneTypeUnsafe()), emptySet())
+
+        // not null for comparisons with constants
+        getRealVariablesForSafeCallChain(operand).takeIf { it.isNotEmpty() }?.let { operandVariables ->
+            operandVariables.forEach { operandVariable ->
+                flow = flow.addNotApprovedFact(
+                    expressionVariable, UnapprovedFirDataFlowInfo(
+                        eq(isEq.toConditionValue()),
+                        operandVariable,
+                        FirDataFlowInfo(setOf(session.builtinTypes.anyType.coneTypeUnsafe()), emptySet())
+                    )
                 )
-            )
+            }
         }
+
+        // propagating facts for (... == true) and (... == false)
+        variableStorage[operand]?.let { operandVariable ->
+            if (const.kind != IrConstKind.Boolean) return@let
+
+            val constValue = (const.value as Boolean)
+            val shouldInvert = isEq xor constValue
+
+            flow.notApprovedFacts[operandVariable].forEach { info ->
+                flow = flow.addNotApprovedFact(expressionVariable, info.let { if (shouldInvert) it.invert() else it })
+            }
+        }
+
         node.flow = flow
     }
 
@@ -217,8 +239,8 @@ class FirDataFlowAnalyzerImpl(transformer: FirBodyResolveTransformer) : FirDataF
         val rightType = rightOperand.typeRef.coneTypeSafe<ConeKotlinType>() ?: return
         when {
             leftType.isMarkedNullable && rightType.isMarkedNullable -> return
-            leftType.isMarkedNullable -> processEqWithConst(node, leftOperand)
-            rightType.isMarkedNullable -> processEqWithConst(node, rightOperand)
+            leftType.isMarkedNullable -> processEqNull(node, leftOperand, FirOperation.NOT_EQ)
+            rightType.isMarkedNullable -> processEqNull(node, rightOperand, FirOperation.NOT_EQ)
         }
         // TODO: process EQUALITY
     }
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.cfg.dot b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.cfg.dot
new file mode 100644
index 00000000000..7cd2da2c0a2
--- /dev/null
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.cfg.dot
@@ -0,0 +1,440 @@
+digraph equalsToBoolean_kt {
+subgraph foo {
+  0 [shape=box label="Enter function foo"];
+  1 [shape=box label="Exit function foo"];
+
+  0 -> {1};
+}
+
+subgraph val_b {
+  2 [shape=box label="Enter property"];
+  3 [shape=box label="Exit property"];
+
+  2 -> {3};
+}
+
+subgraph test_1 {
+  4 [shape=box label="Enter function test_1"];
+  5 [shape=box label="Enter block"];
+  6 [shape=box label="Enter when"];
+  7 [shape=box label="Enter when branch condition "];
+  8 [shape=box label="Access variable R|<local>/b|"];
+  9 [shape=box label="Const: Boolean(true)"];
+  10 [shape=box label="Operator =="];
+  11 [shape=box label="Const: Boolean(true)"];
+  12 [shape=box label="Operator =="];
+  13 [shape=box label="Exit when branch condition"];
+  14 [shape=box label="Enter block"];
+  15 [shape=box label="Access variable R|<local>/b|"];
+  16 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  17 [shape=box label="Exit block"];
+  18 [shape=box label="Exit when branch result"];
+  19 [shape=box label="Enter when branch condition else"];
+  20 [shape=box label="Exit when branch condition"];
+  21 [shape=box label="Enter block"];
+  22 [shape=box label="Access variable R|<local>/b|"];
+  23 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  24 [shape=box label="Exit block"];
+  25 [shape=box label="Exit when branch result"];
+  26 [shape=box label="Exit when"];
+  27 [shape=box label="Exit block"];
+  28 [shape=box label="Exit function test_1"];
+
+  4 -> {5};
+  5 -> {6};
+  6 -> {7};
+  7 -> {8};
+  8 -> {9};
+  9 -> {10};
+  10 -> {11};
+  11 -> {12};
+  12 -> {13};
+  13 -> {14 19};
+  14 -> {15};
+  15 -> {16};
+  16 -> {17};
+  17 -> {18};
+  18 -> {26};
+  19 -> {20};
+  20 -> {21};
+  21 -> {22};
+  22 -> {23};
+  23 -> {24};
+  24 -> {25};
+  25 -> {26};
+  26 -> {27};
+  27 -> {28};
+}
+
+subgraph test_2 {
+  29 [shape=box label="Enter function test_2"];
+  30 [shape=box label="Enter block"];
+  31 [shape=box label="Enter when"];
+  32 [shape=box label="Enter when branch condition "];
+  33 [shape=box label="Access variable R|<local>/b|"];
+  34 [shape=box label="Const: Boolean(true)"];
+  35 [shape=box label="Operator =="];
+  36 [shape=box label="Const: Boolean(true)"];
+  37 [shape=box label="Operator !="];
+  38 [shape=box label="Exit when branch condition"];
+  39 [shape=box label="Enter block"];
+  40 [shape=box label="Access variable R|<local>/b|"];
+  41 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  42 [shape=box label="Exit block"];
+  43 [shape=box label="Exit when branch result"];
+  44 [shape=box label="Enter when branch condition else"];
+  45 [shape=box label="Exit when branch condition"];
+  46 [shape=box label="Enter block"];
+  47 [shape=box label="Access variable R|<local>/b|"];
+  48 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  49 [shape=box label="Exit block"];
+  50 [shape=box label="Exit when branch result"];
+  51 [shape=box label="Exit when"];
+  52 [shape=box label="Exit block"];
+  53 [shape=box label="Exit function test_2"];
+
+  29 -> {30};
+  30 -> {31};
+  31 -> {32};
+  32 -> {33};
+  33 -> {34};
+  34 -> {35};
+  35 -> {36};
+  36 -> {37};
+  37 -> {38};
+  38 -> {39 44};
+  39 -> {40};
+  40 -> {41};
+  41 -> {42};
+  42 -> {43};
+  43 -> {51};
+  44 -> {45};
+  45 -> {46};
+  46 -> {47};
+  47 -> {48};
+  48 -> {49};
+  49 -> {50};
+  50 -> {51};
+  51 -> {52};
+  52 -> {53};
+}
+
+subgraph test_3 {
+  54 [shape=box label="Enter function test_3"];
+  55 [shape=box label="Enter block"];
+  56 [shape=box label="Enter when"];
+  57 [shape=box label="Enter when branch condition "];
+  58 [shape=box label="Access variable R|<local>/b|"];
+  59 [shape=box label="Const: Boolean(true)"];
+  60 [shape=box label="Operator =="];
+  61 [shape=box label="Const: Boolean(false)"];
+  62 [shape=box label="Operator =="];
+  63 [shape=box label="Exit when branch condition"];
+  64 [shape=box label="Enter block"];
+  65 [shape=box label="Access variable R|<local>/b|"];
+  66 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  67 [shape=box label="Exit block"];
+  68 [shape=box label="Exit when branch result"];
+  69 [shape=box label="Enter when branch condition else"];
+  70 [shape=box label="Exit when branch condition"];
+  71 [shape=box label="Enter block"];
+  72 [shape=box label="Access variable R|<local>/b|"];
+  73 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  74 [shape=box label="Exit block"];
+  75 [shape=box label="Exit when branch result"];
+  76 [shape=box label="Exit when"];
+  77 [shape=box label="Exit block"];
+  78 [shape=box label="Exit function test_3"];
+
+  54 -> {55};
+  55 -> {56};
+  56 -> {57};
+  57 -> {58};
+  58 -> {59};
+  59 -> {60};
+  60 -> {61};
+  61 -> {62};
+  62 -> {63};
+  63 -> {64 69};
+  64 -> {65};
+  65 -> {66};
+  66 -> {67};
+  67 -> {68};
+  68 -> {76};
+  69 -> {70};
+  70 -> {71};
+  71 -> {72};
+  72 -> {73};
+  73 -> {74};
+  74 -> {75};
+  75 -> {76};
+  76 -> {77};
+  77 -> {78};
+}
+
+subgraph test_4 {
+  79 [shape=box label="Enter function test_4"];
+  80 [shape=box label="Enter block"];
+  81 [shape=box label="Enter when"];
+  82 [shape=box label="Enter when branch condition "];
+  83 [shape=box label="Access variable R|<local>/b|"];
+  84 [shape=box label="Const: Boolean(true)"];
+  85 [shape=box label="Operator =="];
+  86 [shape=box label="Const: Boolean(false)"];
+  87 [shape=box label="Operator !="];
+  88 [shape=box label="Exit when branch condition"];
+  89 [shape=box label="Enter block"];
+  90 [shape=box label="Access variable R|<local>/b|"];
+  91 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  92 [shape=box label="Exit block"];
+  93 [shape=box label="Exit when branch result"];
+  94 [shape=box label="Enter when branch condition else"];
+  95 [shape=box label="Exit when branch condition"];
+  96 [shape=box label="Enter block"];
+  97 [shape=box label="Access variable R|<local>/b|"];
+  98 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  99 [shape=box label="Exit block"];
+  100 [shape=box label="Exit when branch result"];
+  101 [shape=box label="Exit when"];
+  102 [shape=box label="Exit block"];
+  103 [shape=box label="Exit function test_4"];
+
+  79 -> {80};
+  80 -> {81};
+  81 -> {82};
+  82 -> {83};
+  83 -> {84};
+  84 -> {85};
+  85 -> {86};
+  86 -> {87};
+  87 -> {88};
+  88 -> {89 94};
+  89 -> {90};
+  90 -> {91};
+  91 -> {92};
+  92 -> {93};
+  93 -> {101};
+  94 -> {95};
+  95 -> {96};
+  96 -> {97};
+  97 -> {98};
+  98 -> {99};
+  99 -> {100};
+  100 -> {101};
+  101 -> {102};
+  102 -> {103};
+}
+
+subgraph test_5 {
+  104 [shape=box label="Enter function test_5"];
+  105 [shape=box label="Enter block"];
+  106 [shape=box label="Enter when"];
+  107 [shape=box label="Enter when branch condition "];
+  108 [shape=box label="Access variable R|<local>/b|"];
+  109 [shape=box label="Const: Boolean(true)"];
+  110 [shape=box label="Operator !="];
+  111 [shape=box label="Const: Boolean(true)"];
+  112 [shape=box label="Operator =="];
+  113 [shape=box label="Exit when branch condition"];
+  114 [shape=box label="Enter block"];
+  115 [shape=box label="Access variable R|<local>/b|"];
+  116 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  117 [shape=box label="Exit block"];
+  118 [shape=box label="Exit when branch result"];
+  119 [shape=box label="Enter when branch condition else"];
+  120 [shape=box label="Exit when branch condition"];
+  121 [shape=box label="Enter block"];
+  122 [shape=box label="Access variable R|<local>/b|"];
+  123 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  124 [shape=box label="Exit block"];
+  125 [shape=box label="Exit when branch result"];
+  126 [shape=box label="Exit when"];
+  127 [shape=box label="Exit block"];
+  128 [shape=box label="Exit function test_5"];
+
+  104 -> {105};
+  105 -> {106};
+  106 -> {107};
+  107 -> {108};
+  108 -> {109};
+  109 -> {110};
+  110 -> {111};
+  111 -> {112};
+  112 -> {113};
+  113 -> {114 119};
+  114 -> {115};
+  115 -> {116};
+  116 -> {117};
+  117 -> {118};
+  118 -> {126};
+  119 -> {120};
+  120 -> {121};
+  121 -> {122};
+  122 -> {123};
+  123 -> {124};
+  124 -> {125};
+  125 -> {126};
+  126 -> {127};
+  127 -> {128};
+}
+
+subgraph test_6 {
+  129 [shape=box label="Enter function test_6"];
+  130 [shape=box label="Enter block"];
+  131 [shape=box label="Enter when"];
+  132 [shape=box label="Enter when branch condition "];
+  133 [shape=box label="Access variable R|<local>/b|"];
+  134 [shape=box label="Const: Boolean(true)"];
+  135 [shape=box label="Operator !="];
+  136 [shape=box label="Const: Boolean(true)"];
+  137 [shape=box label="Operator !="];
+  138 [shape=box label="Exit when branch condition"];
+  139 [shape=box label="Enter block"];
+  140 [shape=box label="Access variable R|<local>/b|"];
+  141 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  142 [shape=box label="Exit block"];
+  143 [shape=box label="Exit when branch result"];
+  144 [shape=box label="Enter when branch condition else"];
+  145 [shape=box label="Exit when branch condition"];
+  146 [shape=box label="Enter block"];
+  147 [shape=box label="Access variable R|<local>/b|"];
+  148 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  149 [shape=box label="Exit block"];
+  150 [shape=box label="Exit when branch result"];
+  151 [shape=box label="Exit when"];
+  152 [shape=box label="Exit block"];
+  153 [shape=box label="Exit function test_6"];
+
+  129 -> {130};
+  130 -> {131};
+  131 -> {132};
+  132 -> {133};
+  133 -> {134};
+  134 -> {135};
+  135 -> {136};
+  136 -> {137};
+  137 -> {138};
+  138 -> {139 144};
+  139 -> {140};
+  140 -> {141};
+  141 -> {142};
+  142 -> {143};
+  143 -> {151};
+  144 -> {145};
+  145 -> {146};
+  146 -> {147};
+  147 -> {148};
+  148 -> {149};
+  149 -> {150};
+  150 -> {151};
+  151 -> {152};
+  152 -> {153};
+}
+
+subgraph test_7 {
+  154 [shape=box label="Enter function test_7"];
+  155 [shape=box label="Enter block"];
+  156 [shape=box label="Enter when"];
+  157 [shape=box label="Enter when branch condition "];
+  158 [shape=box label="Access variable R|<local>/b|"];
+  159 [shape=box label="Const: Boolean(true)"];
+  160 [shape=box label="Operator !="];
+  161 [shape=box label="Const: Boolean(false)"];
+  162 [shape=box label="Operator =="];
+  163 [shape=box label="Exit when branch condition"];
+  164 [shape=box label="Enter block"];
+  165 [shape=box label="Access variable R|<local>/b|"];
+  166 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  167 [shape=box label="Exit block"];
+  168 [shape=box label="Exit when branch result"];
+  169 [shape=box label="Enter when branch condition else"];
+  170 [shape=box label="Exit when branch condition"];
+  171 [shape=box label="Enter block"];
+  172 [shape=box label="Access variable R|<local>/b|"];
+  173 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  174 [shape=box label="Exit block"];
+  175 [shape=box label="Exit when branch result"];
+  176 [shape=box label="Exit when"];
+  177 [shape=box label="Exit block"];
+  178 [shape=box label="Exit function test_7"];
+
+  154 -> {155};
+  155 -> {156};
+  156 -> {157};
+  157 -> {158};
+  158 -> {159};
+  159 -> {160};
+  160 -> {161};
+  161 -> {162};
+  162 -> {163};
+  163 -> {164 169};
+  164 -> {165};
+  165 -> {166};
+  166 -> {167};
+  167 -> {168};
+  168 -> {176};
+  169 -> {170};
+  170 -> {171};
+  171 -> {172};
+  172 -> {173};
+  173 -> {174};
+  174 -> {175};
+  175 -> {176};
+  176 -> {177};
+  177 -> {178};
+}
+
+subgraph test_8 {
+  179 [shape=box label="Enter function test_8"];
+  180 [shape=box label="Enter block"];
+  181 [shape=box label="Enter when"];
+  182 [shape=box label="Enter when branch condition "];
+  183 [shape=box label="Access variable R|<local>/b|"];
+  184 [shape=box label="Const: Boolean(true)"];
+  185 [shape=box label="Operator !="];
+  186 [shape=box label="Const: Boolean(false)"];
+  187 [shape=box label="Operator !="];
+  188 [shape=box label="Exit when branch condition"];
+  189 [shape=box label="Enter block"];
+  190 [shape=box label="Access variable R|<local>/b|"];
+  191 [shape=box label="Function call: R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()"];
+  192 [shape=box label="Exit block"];
+  193 [shape=box label="Exit when branch result"];
+  194 [shape=box label="Enter when branch condition else"];
+  195 [shape=box label="Exit when branch condition"];
+  196 [shape=box label="Enter block"];
+  197 [shape=box label="Access variable R|<local>/b|"];
+  198 [shape=box label="Function call: R|<local>/b|.R|kotlin/Boolean.not|()"];
+  199 [shape=box label="Exit block"];
+  200 [shape=box label="Exit when branch result"];
+  201 [shape=box label="Exit when"];
+  202 [shape=box label="Exit block"];
+  203 [shape=box label="Exit function test_8"];
+
+  179 -> {180};
+  180 -> {181};
+  181 -> {182};
+  182 -> {183};
+  183 -> {184};
+  184 -> {185};
+  185 -> {186};
+  186 -> {187};
+  187 -> {188};
+  188 -> {189 194};
+  189 -> {190};
+  190 -> {191};
+  191 -> {192};
+  192 -> {193};
+  193 -> {201};
+  194 -> {195};
+  195 -> {196};
+  196 -> {197};
+  197 -> {198};
+  198 -> {199};
+  199 -> {200};
+  200 -> {201};
+  201 -> {202};
+  202 -> {203};
+}
+
+}
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.kt b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.kt
new file mode 100644
index 00000000000..05614a38909
--- /dev/null
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.kt
@@ -0,0 +1,68 @@
+interface A {
+    fun foo()
+    val b: Boolean
+}
+
+fun test_1(b: Boolean?) {
+    if ((b == true) == true) {
+        b.not() // OK
+    } else {
+        b.not() // Bad
+    }
+}
+
+fun test_2(b: Boolean?) {
+    if ((b == true) != true) {
+        b.not() // Bad
+    } else {
+        b.not() // OK
+    }
+}
+
+fun test_3(b: Boolean?) {
+    if ((b == true) == false) {
+        b.not() // Bad
+    } else {
+        b.not() // OK
+    }
+}
+
+fun test_4(b: Boolean?) {
+    if ((b == true) != false) {
+        b.not() // OK
+    } else {
+        b.not() // Bad
+    }
+}
+
+fun test_5(b: Boolean?) {
+    if ((b != true) == true) {
+        b.not() // Bad
+    } else {
+        b.not() // OK
+    }
+}
+
+fun test_6(b: Boolean?) {
+    if ((b != true) != true) {
+        b.not() // OK
+    } else {
+        b.not() // Bad
+    }
+}
+
+fun test_7(b: Boolean?) {
+    if ((b != true) == false) {
+        b.not() // OK
+    } else {
+        b.not() // Bad
+    }
+}
+
+fun test_8(b: Boolean?) {
+    if ((b != true) != false) {
+        b.not() // Bad
+    } else {
+        b.not() // OK
+    }
+}
\ No newline at end of file
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.txt b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.txt
new file mode 100644
index 00000000000..543533b04fb
--- /dev/null
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.txt
@@ -0,0 +1,96 @@
+FILE: equalsToBoolean.kt
+    public abstract interface A : R|kotlin/Any| {
+        public abstract fun foo(): R|kotlin/Unit|
+
+        public abstract val b: R|kotlin/Boolean|
+            public get(): R|kotlin/Boolean|
+
+    }
+    public final fun test_1(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            ==(==(R|<local>/b|, Boolean(true)), Boolean(true)) ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+            else ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+        }
+
+    }
+    public final fun test_2(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            !=(==(R|<local>/b|, Boolean(true)), Boolean(true)) ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+            else ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+        }
+
+    }
+    public final fun test_3(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            ==(==(R|<local>/b|, Boolean(true)), Boolean(false)) ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+            else ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+        }
+
+    }
+    public final fun test_4(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            !=(==(R|<local>/b|, Boolean(true)), Boolean(false)) ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+            else ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+        }
+
+    }
+    public final fun test_5(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            ==(!=(R|<local>/b|, Boolean(true)), Boolean(true)) ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+            else ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+        }
+
+    }
+    public final fun test_6(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            !=(!=(R|<local>/b|, Boolean(true)), Boolean(true)) ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+            else ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+        }
+
+    }
+    public final fun test_7(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            ==(!=(R|<local>/b|, Boolean(true)), Boolean(false)) ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+            else ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+        }
+
+    }
+    public final fun test_8(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
+        when () {
+            !=(!=(R|<local>/b|, Boolean(true)), Boolean(false)) ->  {
+                R|<local>/b|.<Inapplicable(WRONG_RECEIVER): [kotlin/Boolean.not]>#()
+            }
+            else ->  {
+                R|<local>/b|.R|kotlin/Boolean.not|()
+            }
+        }
+
+    }
diff --git a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java
index b885b01b970..41b54ad6103 100644
--- a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java
+++ b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java
@@ -119,6 +119,11 @@ public class FirCfgBuildingTestGenerated extends AbstractFirCfgBuildingTest {
             runTest("compiler/fir/resolve/testData/resolve/smartcasts/equalsAndIdentity.kt");
         }
 
+        @TestMetadata("equalsToBoolean.kt")
+        public void testEqualsToBoolean() throws Exception {
+            runTest("compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.kt");
+        }
+
         @TestMetadata("inPlaceLambdas.kt")
         public void testInPlaceLambdas() throws Exception {
             runTest("compiler/fir/resolve/testData/resolve/smartcasts/inPlaceLambdas.kt");