[FIR] Implement checks for contract not allowed

^KT-55423 Fixed

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

@@ -3678,6 +3678,13 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.CONTRACT_NOT_ALLOWED) { firDiagnostic ->
+        ContractNotAllowedImpl(
+            firDiagnostic.a,
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.NO_GET_METHOD) { firDiagnostic ->
         NoGetMethodImpl(
             firDiagnostic as KtPsiDiagnostic,

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

@@ -2567,6 +2567,11 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val reason: String
     }
 
+    abstract class ContractNotAllowed : KtFirDiagnostic<KtElement>() {
+        override val diagnosticClass get() = ContractNotAllowed::class
+        abstract val reason: String
+    }
+
     abstract class NoGetMethod : KtFirDiagnostic<KtArrayAccessExpression>() {
         override val diagnosticClass get() = NoGetMethod::class
     }

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

@@ -3096,6 +3096,12 @@ internal class ErrorInContractDescriptionImpl(
     override val token: KtLifetimeToken,
 ) : KtFirDiagnostic.ErrorInContractDescription(), KtAbstractFirDiagnostic<KtElement>
 
+internal class ContractNotAllowedImpl(
+    override val reason: String,
+    override val firDiagnostic: KtPsiDiagnostic,
+    override val token: KtLifetimeToken,
+) : KtFirDiagnostic.ContractNotAllowed(), KtAbstractFirDiagnostic<KtElement>
+
 internal class NoGetMethodImpl(
     override val firDiagnostic: KtPsiDiagnostic,
     override val token: KtLifetimeToken,

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/lazy/resolve/FirLazyBodiesCalculator.kt

@@ -107,6 +107,7 @@ internal object FirLazyBodiesCalculator {
 
         constructor.apply {
             replaceBody(newConstructor.body)
+            replaceContractDescription(newConstructor.contractDescription)
             replaceDelegatedConstructor(newConstructor.delegatedConstructor)
             replaceValueParameterDefaultValues(valueParameters, newConstructor.valueParameters)
         }