[FIR] Fix NPE on invalid gets with index

^KT-60342 fixed

analysis/analysis-api-fe10/tests-gen/org/jetbrains/kotlin/analysis/api/fe10/test/cases/generated/cases/components/expressionTypeProvider/Fe10IdeNormalAnalysisSourceModuleHLExpressionTypeTestGenerated.java

@@ -100,6 +100,12 @@ public class Fe10IdeNormalAnalysisSourceModuleHLExpressionTypeTestGenerated exte
         runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/inParens.kt");
     }
 
+    @Test
+    @TestMetadata("incompleteGet.kt")
+    public void testIncompleteGet() throws Exception {
+        runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/incompleteGet.kt");
+    }
+
     @Test
     @TestMetadata("insideStringTemplate.kt")
     public void testInsideStringTemplate() throws Exception {

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirExpressionTypeProvider.kt

@@ -154,7 +154,7 @@ internal class KtFirExpressionTypeProvider(
         val assignment = expression.parent as? KtBinaryExpression ?: return null
         if (assignment.operationToken !in KtTokens.ALL_ASSIGNMENTS) return null
         if (assignment.left != expression) return null
-        val setTargetParameterType = fir.argumentsToSubstitutedValueParameters()?.values?.last()?.substitutedType ?: return null
+        val setTargetParameterType = fir.argumentsToSubstitutedValueParameters()?.values?.lastOrNull()?.substitutedType ?: return null
         return setTargetParameterType.asKtType()
     }
 

analysis/analysis-api-fir/tests-gen/org/jetbrains/kotlin/analysis/api/fir/test/cases/generated/cases/components/expressionTypeProvider/FirIdeDependentAnalysisSourceModuleHLExpressionTypeTestGenerated.java

@@ -100,6 +100,12 @@ public class FirIdeDependentAnalysisSourceModuleHLExpressionTypeTestGenerated ex
         runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/inParens.kt");
     }
 
+    @Test
+    @TestMetadata("incompleteGet.kt")
+    public void testIncompleteGet() throws Exception {
+        runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/incompleteGet.kt");
+    }
+
     @Test
     @TestMetadata("insideStringTemplate.kt")
     public void testInsideStringTemplate() throws Exception {

analysis/analysis-api-fir/tests-gen/org/jetbrains/kotlin/analysis/api/fir/test/cases/generated/cases/components/expressionTypeProvider/FirIdeNormalAnalysisSourceModuleHLExpressionTypeTestGenerated.java

@@ -100,6 +100,12 @@ public class FirIdeNormalAnalysisSourceModuleHLExpressionTypeTestGenerated exten
         runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/inParens.kt");
     }
 
+    @Test
+    @TestMetadata("incompleteGet.kt")
+    public void testIncompleteGet() throws Exception {
+        runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/incompleteGet.kt");
+    }
+
     @Test
     @TestMetadata("insideStringTemplate.kt")
     public void testInsideStringTemplate() throws Exception {

analysis/analysis-api-standalone/tests-gen/org/jetbrains/kotlin/analysis/api/standalone/fir/test/cases/generated/cases/components/expressionTypeProvider/FirStandaloneNormalAnalysisSourceModuleHLExpressionTypeTestGenerated.java

@@ -100,6 +100,12 @@ public class FirStandaloneNormalAnalysisSourceModuleHLExpressionTypeTestGenerate
         runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/inParens.kt");
     }
 
+    @Test
+    @TestMetadata("incompleteGet.kt")
+    public void testIncompleteGet() throws Exception {
+        runTest("analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/incompleteGet.kt");
+    }
+
     @Test
     @TestMetadata("insideStringTemplate.kt")
     public void testInsideStringTemplate() throws Exception {

analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/incompleteGet.kt

@@ -0,0 +1,9 @@
+class Incomplete {
+    fun get{}
+}
+
+
+fun main(args: Array<String>) {
+    var incomplete: Incomplete = Incomplete(1)
+    <expr>incomplete[0]</expr> += 1
+}

analysis/analysis-api/testData/components/expressionTypeProvider/expressionType/incompleteGet.txt

@@ -0,0 +1,2 @@
+expression: incomplete[0]
+type: kotlin.Unit