[FIR] Make UNSAFE_INFIX_CALL and UNSAFE_OPERATOR_CALL parameter nullable

This fixes an NPE in the IDE in presence of a syntax error when the
argument expression has no source.

#KT-64062 Fixed

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -4045,7 +4045,7 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             firSymbolBuilder.typeBuilder.buildKtType(firDiagnostic.a),
             firDiagnostic.b.source!!.psi as KtExpression,
             firDiagnostic.c,
-            firDiagnostic.d.source!!.psi as KtExpression,
+            firDiagnostic.d?.source?.psi as? KtExpression,
             firDiagnostic as KtPsiDiagnostic,
             token,
         )
@@ -4055,7 +4055,7 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             firSymbolBuilder.typeBuilder.buildKtType(firDiagnostic.a),
             firDiagnostic.b.source!!.psi as KtExpression,
             firDiagnostic.c,
-            firDiagnostic.d.source!!.psi as KtExpression,
+            firDiagnostic.d?.source?.psi as? KtExpression,
             firDiagnostic as KtPsiDiagnostic,
             token,
         )

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -2822,7 +2822,7 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         val receiverType: KtType
         val receiverExpression: KtExpression
         val operator: String
-        val argumentExpression: KtExpression
+        val argumentExpression: KtExpression?
     }
 
     interface UnsafeOperatorCall : KtFirDiagnostic<KtExpression> {
@@ -2830,7 +2830,7 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         val receiverType: KtType
         val receiverExpression: KtExpression
         val operator: String
-        val argumentExpression: KtExpression
+        val argumentExpression: KtExpression?
     }
 
     interface IteratorOnNullable : KtFirDiagnostic<KtExpression> {

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -3396,7 +3396,7 @@ internal class UnsafeInfixCallImpl(
     override val receiverType: KtType,
     override val receiverExpression: KtExpression,
     override val operator: String,
-    override val argumentExpression: KtExpression,
+    override val argumentExpression: KtExpression?,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtExpression>(firDiagnostic, token), KtFirDiagnostic.UnsafeInfixCall
@@ -3405,7 +3405,7 @@ internal class UnsafeOperatorCallImpl(
     override val receiverType: KtType,
     override val receiverExpression: KtExpression,
     override val operator: String,
-    override val argumentExpression: KtExpression,
+    override val argumentExpression: KtExpression?,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtExpression>(firDiagnostic, token), KtFirDiagnostic.UnsafeOperatorCall

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

@@ -26348,6 +26348,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
                 runTest("compiler/testData/diagnostics/tests/nullableTypes/takingNullabilityFromExplicitTypeArgmentsInsteadOfUsingFlexibleTypes.kt");
             }
 
+            @Test
+            @TestMetadata("unsafeCallOnOperatorRedCode.kt")
+            public void testUnsafeCallOnOperatorRedCode() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/nullableTypes/unsafeCallOnOperatorRedCode.kt");
+            }
+
             @Test
             @TestMetadata("uselessElvis.kt")
             public void testUselessElvis() throws Exception {

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

@@ -26348,6 +26348,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
                 runTest("compiler/testData/diagnostics/tests/nullableTypes/takingNullabilityFromExplicitTypeArgmentsInsteadOfUsingFlexibleTypes.kt");
             }
 
+            @Test
+            @TestMetadata("unsafeCallOnOperatorRedCode.kt")
+            public void testUnsafeCallOnOperatorRedCode() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/nullableTypes/unsafeCallOnOperatorRedCode.kt");
+            }
+
             @Test
             @TestMetadata("uselessElvis.kt")
             public void testUselessElvis() throws Exception {