[FIR] Fix the user project failure

The problem is caused by
`FirExpression.tryToSetSourceForImplicitReceiver()`:
at some point a smartcast expression is
instantiated with an `originalExpression`
with no source, but later it's replaced
with a one that does have a one,
which leads to inconsistency.

Also the receiver expression may have `null` source
instead of a fake source, which can also make
`FirJvmModuleAccessibilityTypeChecker` fail.

The change in `FirElementsRecorder` is
backed by:
`K2HighlightingMetaInfoTestGenerated.testImplicitAndExplicit_functions`
(otherwise `descr='Implicit receiver smart cast to Foo'`
is replaced with `descr='Smart cast to Foo'`),
as well as:
- `testImplicitAndExplicit_operators`
- `testImplicitAndExplicit_properties`
- `testImplicit_stable`
and `K2IdeK2CodeKotlinSteppingTestGenerated$Custom.testSmartStepIntoInterfaceImpl`.

The new `ImplicitThisReceiverExpression`
was introduced, because for some reason
assigning non-`-1` offsets to the
`IrGetValue` expressions (in
`Fir2IrVisitor.generateThisReceiverAccessForCallable`) in
`FirLightTreeBlackBoxInlineCodegenWithIrInlinerTestGenerated.testAnonymousObjectInCallChildren`
leads to incorrect SMAP generation:
when in `AbstractClassBuilder.visitSMAP`,
we can see that some `RangeMapping` are
incorrect in a sence that this code doesn't
expect them to be like this for some reason.
This is important because it also affects
the following pair of tests in intelij:

- `K1IdeK2CodeKotlinSteppingTestGenerated.StepInto#testKotlinSamFunction`
- `K1IdeK2CodeKotlinSteppingTestGenerated.SmartStepInto#testKotlinSamFunction`

These tests under the hood rely on a single
test file, and with such line numbers it's
impossible to satisfy them both at once:
they produce 2 contradicting changes. Namely,
the first one leads to:

```
kotlinSamFunction.kt:15
kotlinSamFunction.kt:6
resuming kotlinSamFunction.kt:15
Disconnected from the target VM
```

...while the second one - to:

```
kotlinSamFunction.kt:15
kotlinSamFunction.kt:15
Disconnected from the target VM
```

^KT-67469 Fixed

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/file/structure/FirElementsRecorder.kt

@@ -125,7 +125,7 @@ internal open class FirElementsRecorder : FirVisitor<Unit, MutableMap<KtElement,
                         // For secondary constructors without explicit delegated constructor call, the PSI tree always create an empty
                         // KtConstructorDelegationCall. In this case, the source in FIR has this fake source kind.
                         it.kind == KtFakeSourceElementKind.ImplicitConstructor ||
-                        it.kind == KtFakeSourceElementKind.SmartCastExpression ||
+                        it.isSourceForSmartCasts(element) ||
                         it.kind == KtFakeSourceElementKind.DanglingModifierList ||
                         it.isSourceForArrayAugmentedAssign(element) ||
                         it.isSourceForCompoundAccess(element)
@@ -161,6 +161,16 @@ internal open class FirElementsRecorder : FirVisitor<Unit, MutableMap<KtElement,
         // We need to filter it out to map this source element to set/plusAssign call, so we check `is FirFunctionCall`
         (kind is KtFakeSourceElementKind.DesugaredAugmentedAssign) && fir is FirFunctionCall
 
+    // `FirSmartCastExpression` forward the source from the original expression,
+    // and implicit receivers have fake sources pointing to a wider part of the expression.
+    // Thus, `FirElementsRecorder` may try assigning an unnecessarily wide source
+    // to smart cast expressions, which will affect the
+    // `org.jetbrains.kotlin.idea.highlighting.highlighters.ExpressionsSmartcastHighlighter#highlightExpression`
+    // function in intellij.git
+    private fun KtSourceElement.isSourceForSmartCasts(fir: FirElement) =
+        (kind is KtFakeSourceElementKind.SmartCastExpression) && fir is FirSmartCastExpression && !fir.originalExpression.isImplicitThisReceiver
+
+    private val FirExpression.isImplicitThisReceiver get() = this is FirThisReceiverExpression && this.isImplicit
 
     private fun FirElement.isReadInCompoundCall(): Boolean {
         if (this is FirPropertyAccessExpression) return true

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt

@@ -94,7 +94,11 @@ internal inline fun <T : IrElement> KtSourceElement?.convertWithOffsets(f: (star
     val startOffset: Int
     val endOffset: Int
 
-    if (isCompiledElement(psi) || this?.kind == KtFakeSourceElementKind.DataClassGeneratedMembers) {
+    if (
+        isCompiledElement(psi) ||
+        this?.kind == KtFakeSourceElementKind.DataClassGeneratedMembers ||
+        this?.kind == KtFakeSourceElementKind.ImplicitThisReceiverExpression
+    ) {
         startOffset = UNDEFINED_OFFSET
         endOffset = UNDEFINED_OFFSET
     } else {

compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt

@@ -180,13 +180,16 @@ private fun receiverExpression(
         boundSymbol = symbol
         this.contextReceiverNumber = contextReceiverNumber
     }
+    val newSource = symbol.source?.fakeElement(KtFakeSourceElementKind.ImplicitThisReceiverExpression)
     return when (inaccessibleReceiver) {
         false -> buildThisReceiverExpression {
+            source = newSource
             this.calleeReference = calleeReference
             this.coneTypeOrNull = type
             isImplicit = true
         }
         true -> buildInaccessibleReceiverExpression {
+            source = newSource
             this.calleeReference = calleeReference
             this.coneTypeOrNull = type
         }

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirSmartCastExpressionImpl.kt

@@ -37,7 +37,8 @@ internal class FirSmartCastExpressionImpl(
     override var smartcastTypeWithoutNullableNothing: FirTypeRef?,
     override val smartcastStability: SmartcastStability,
 ) : FirSmartCastExpression() {
-    override val source: KtSourceElement? = originalExpression.source?.fakeElement(KtFakeSourceElementKind.SmartCastExpression)
+    override val source: KtSourceElement?
+        get() = originalExpression.source?.fakeElement(KtFakeSourceElementKind.SmartCastExpression)
     override val isStable: Boolean
         get() = smartcastStability == SmartcastStability.STABLE_VALUE
 

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt

@@ -440,6 +440,7 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
             }
             default("source") {
                 value = "originalExpression.source?.fakeElement(KtFakeSourceElementKind.SmartCastExpression)"
+                withGetter = true
             }
             additionalImports(fakeElementImport, fakeSourceElementKindImport)
         }

compiler/frontend.common/src/org/jetbrains/kotlin/KtSourceElement.kt

@@ -42,6 +42,9 @@ sealed class KtFakeSourceElementKind(final override val shouldSkipErrorTypeRepor
     // destruction parameters, function literals, explicitly boolean expressions
     object ImplicitTypeRef : KtFakeSourceElementKind(shouldSkipErrorTypeReporting = true)
 
+    // for errors on smartcast types then the type is brought in by an implicit this receiver expression
+    object ImplicitThisReceiverExpression : KtFakeSourceElementKind(shouldSkipErrorTypeReporting = false)
+
     // for type arguments that were inferred as opposed to specified
     // explicitly via `<>`
     object ImplicitTypeArgument : KtFakeSourceElementKind()