[FIR] Fix invalid expression throwing exception when determining type

^KTIJ-25421 fixed

Merge-request: KT-MR-10317
Merged-by: Egor Kulikov <Egor.Kulikov@jetbrains.com>

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

@@ -74,19 +74,24 @@ internal class KtFirExpressionTypeProvider(
             is FirNamedReference -> fir.getReferencedElementType().asKtType()
             is FirStatement -> with(analysisSession) { builtinTypes.UNIT }
             is FirTypeRef, is FirImport, is FirPackageDirective, is FirLabel, is FirTypeParameterRef -> null
-            // For invalid code like the following,
+
+            // `listOf<_>(1)` where `expression` is `_`
+            is FirPlaceholderProjection -> null
+
+            // There are various cases where we have no corresponding fir due to invalid code
+            // Some examples:
             // ```
             // when {
             //   true, false -> {}
             // }
             // ```
-            // `false` does not have a corresponding elements on the FIR side and hence the containing `FirWhenBranch` is returned. In this
-            // case, we simply report null since FIR does not know about it.
-            is FirWhenBranch -> null
-
-            // `listOf<_>(1)` where `expression` is `_`
-            is FirPlaceholderProjection -> null
-            else -> error("Unexpected ${fir?.let { it::class }} for ${expression::class} with text `${expression.text}`")
+            // `false` does not have a corresponding elements on the FIR side and hence the containing `FirWhenBranch` is returned.
+            // ```
+            // @Volatile
+            // private var
+            // ```
+            // Volatile does not have corresponding element, so `FirFileImpl` is returned
+            else -> null
         }
     }
 

analysis/low-level-api-fir/testdata/getOrBuildFir/invalidCode/incompletePropertyWithAnnotation.kt

@@ -0,0 +1,2 @@
+@<expr>Volatile</expr>
+private var

analysis/low-level-api-fir/testdata/getOrBuildFir/invalidCode/incompletePropertyWithAnnotation.txt

@@ -0,0 +1,6 @@
+KT element: KtConstructorCalleeExpression
+FIR element: FirAnnotationCallImpl
+FIR source kind: KtRealSourceElementKind
+
+FIR element rendered:
+@<ERROR TYPE REF: Symbol not found for Volatile>[Types]()

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/OutOfContentRootGetOrBuildFirTestGenerated.java

@@ -805,6 +805,12 @@ public class OutOfContentRootGetOrBuildFirTestGenerated extends AbstractOutOfCon
             runTest("analysis/low-level-api-fir/testdata/getOrBuildFir/invalidCode/delegatedProperty.kt");
         }
 
+        @Test
+        @TestMetadata("incompletePropertyWithAnnotation.kt")
+        public void testIncompletePropertyWithAnnotation() throws Exception {
+            runTest("analysis/low-level-api-fir/testdata/getOrBuildFir/invalidCode/incompletePropertyWithAnnotation.kt");
+        }
+
         @Test
         @TestMetadata("javaClassLiteral.kt")
         public void testJavaClassLiteral() throws Exception {

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/SourceGetOrBuildFirTestGenerated.java

@@ -805,6 +805,12 @@ public class SourceGetOrBuildFirTestGenerated extends AbstractSourceGetOrBuildFi
             runTest("analysis/low-level-api-fir/testdata/getOrBuildFir/invalidCode/delegatedProperty.kt");
         }
 
+        @Test
+        @TestMetadata("incompletePropertyWithAnnotation.kt")
+        public void testIncompletePropertyWithAnnotation() throws Exception {
+            runTest("analysis/low-level-api-fir/testdata/getOrBuildFir/invalidCode/incompletePropertyWithAnnotation.kt");
+        }
+
         @Test
         @TestMetadata("javaClassLiteral.kt")
         public void testJavaClassLiteral() throws Exception {