[FIR] Add equality constraint from expected type for some synthetic function calls

This fixes some cases where we infer some type variable inside one
of the branches to Nothing instead of the expected type because Nothing
appeared in some other branch.

Specifically, we add an equality instead of a subtype constraint during
completion of calls to synthetic functions for if/when, try and !!.
We don't do it when the call contains a (possibly nested) elvis or is
inside the RHS of an assignment.
Otherwise, we would prevent some smart-casts.

#KT-65882 Fixed

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java

@@ -16652,6 +16652,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
         runTest("compiler/testData/diagnostics/tests/inference/capturedTypesInSelfType.kt");
       }
 
+      @Test
+      @TestMetadata("checkNotNullWithNullableExpectedType.kt")
+      public void testCheckNotNullWithNullableExpectedType() {
+        runTest("compiler/testData/diagnostics/tests/inference/checkNotNullWithNullableExpectedType.kt");
+      }
+
       @Test
       @TestMetadata("coerceFunctionLiteralToSuspend.kt")
       public void testCoerceFunctionLiteralToSuspend() {
@@ -17174,6 +17180,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
         runTest("compiler/testData/diagnostics/tests/inference/mostSpecificAfterInference.kt");
       }
 
+      @Test
+      @TestMetadata("nestedIfWithExpectedType.kt")
+      public void testNestedIfWithExpectedType() {
+        runTest("compiler/testData/diagnostics/tests/inference/nestedIfWithExpectedType.kt");
+      }
+
       @Test
       @TestMetadata("NoInferenceFromDeclaredBounds.kt")
       public void testNoInferenceFromDeclaredBounds() {
@@ -18982,6 +18994,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
         public void testWrongApproximationWithDefNotNullTypesAndDelegates() {
           runTest("compiler/testData/diagnostics/tests/inference/constraints/wrongApproximationWithDefNotNullTypesAndDelegates.kt");
         }
+
+        @Test
+        @TestMetadata("wrongExpectedTypeForWhen.kt")
+        public void testWrongExpectedTypeForWhen() {
+          runTest("compiler/testData/diagnostics/tests/inference/constraints/wrongExpectedTypeForWhen.kt");
+        }
       }
 
       @Nested

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirBlackBoxCodegenBasedTestGenerated.java

@@ -23888,6 +23888,12 @@ public class LLFirBlackBoxCodegenBasedTestGenerated extends AbstractLLFirBlackBo
       runTest("compiler/testData/codegen/box/inference/kt51040.kt");
     }
 
+    @Test
+    @TestMetadata("kt65882.kt")
+    public void testKt65882() {
+      runTest("compiler/testData/codegen/box/inference/kt65882.kt");
+    }
+
     @Test
     @TestMetadata("lambdaWithStarReturn.kt")
     public void testLambdaWithStarReturn() {

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java

@@ -16652,6 +16652,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
         runTest("compiler/testData/diagnostics/tests/inference/capturedTypesInSelfType.kt");
       }
 
+      @Test
+      @TestMetadata("checkNotNullWithNullableExpectedType.kt")
+      public void testCheckNotNullWithNullableExpectedType() {
+        runTest("compiler/testData/diagnostics/tests/inference/checkNotNullWithNullableExpectedType.kt");
+      }
+
       @Test
       @TestMetadata("coerceFunctionLiteralToSuspend.kt")
       public void testCoerceFunctionLiteralToSuspend() {
@@ -17174,6 +17180,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
         runTest("compiler/testData/diagnostics/tests/inference/mostSpecificAfterInference.kt");
       }
 
+      @Test
+      @TestMetadata("nestedIfWithExpectedType.kt")
+      public void testNestedIfWithExpectedType() {
+        runTest("compiler/testData/diagnostics/tests/inference/nestedIfWithExpectedType.kt");
+      }
+
       @Test
       @TestMetadata("NoInferenceFromDeclaredBounds.kt")
       public void testNoInferenceFromDeclaredBounds() {
@@ -18982,6 +18994,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
         public void testWrongApproximationWithDefNotNullTypesAndDelegates() {
           runTest("compiler/testData/diagnostics/tests/inference/constraints/wrongApproximationWithDefNotNullTypesAndDelegates.kt");
         }
+
+        @Test
+        @TestMetadata("wrongExpectedTypeForWhen.kt")
+        public void testWrongExpectedTypeForWhen() {
+          runTest("compiler/testData/diagnostics/tests/inference/constraints/wrongExpectedTypeForWhen.kt");
+        }
       }
 
       @Nested

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirReversedBlackBoxCodegenBasedTestGenerated.java

@@ -23888,6 +23888,12 @@ public class LLFirReversedBlackBoxCodegenBasedTestGenerated extends AbstractLLFi
       runTest("compiler/testData/codegen/box/inference/kt51040.kt");
     }
 
+    @Test
+    @TestMetadata("kt65882.kt")
+    public void testKt65882() {
+      runTest("compiler/testData/codegen/box/inference/kt65882.kt");
+    }
+
     @Test
     @TestMetadata("lambdaWithStarReturn.kt")
     public void testLambdaWithStarReturn() {