[FIR] Forbid generic type checks inside contracts in K2 as it is done in K1.

#KT-59922

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirCastOperatorsChecker.kt

@@ -48,7 +48,7 @@ object FirCastOperatorsChecker : FirTypeOperatorCallChecker() {
                 reporter.reportOn(expression.source, FirErrors.UNCHECKED_CAST, actualType, targetType, context)
             }
         } else if (expression.operation == FirOperation.IS) {
-            if (!context.isContractBody && isCastErased(actualType, targetType, context)) {
+            if (isCastErased(actualType, targetType, context)) {
                 reporter.reportOn(conversionTypeRef.source, FirErrors.CANNOT_CHECK_FOR_ERASED, targetType, context)
             }
         }

compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/errors/typeReferences.1.3.fir.kt

@@ -13,14 +13,14 @@ inline fun <reified T> referToReifiedGeneric(x: Any?) {
 class Generic<T> {
     fun referToCaptured(x: Any?) {
         contract {
-            <!ERROR_IN_CONTRACT_DESCRIPTION!>returns() implies (x is T)<!>
+            <!ERROR_IN_CONTRACT_DESCRIPTION!>returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>T<!>)<!>
         }
     }
 }
 
 fun referToSubstituted(x: Any?) {
     contract {
-        returns() implies (x is Generic<String>)
+        returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>Generic<String><!>)
     }
 }
 
@@ -36,13 +36,13 @@ typealias SimpleType = Int
 
 fun referToAliasedGeneric(x: Any?) {
     contract {
-        returns() implies (x is GenericString)
+        returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>GenericString<!>)
     }
 }
 
 fun referToAliasedFunctionType(x: Any?) {
     contract {
-        returns() implies (x is FunctionalType)
+        returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>FunctionalType<!>)
     }
 }
 

compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/errors/typeReferences.1.4.fir.kt

@@ -13,14 +13,14 @@ inline fun <reified T> referToReifiedGeneric(x: Any?) {
 class Generic<T> {
     fun referToCaptured(x: Any?) {
         contract {
-            <!ERROR_IN_CONTRACT_DESCRIPTION!>returns() implies (x is T)<!>
+            <!ERROR_IN_CONTRACT_DESCRIPTION!>returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>T<!>)<!>
         }
     }
 }
 
 fun referToSubstituted(x: Any?) {
     contract {
-        returns() implies (x is Generic<String>)
+        returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>Generic<String><!>)
     }
 }
 
@@ -36,13 +36,13 @@ typealias SimpleType = Int
 
 fun referToAliasedGeneric(x: Any?) {
     contract {
-        returns() implies (x is GenericString)
+        returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>GenericString<!>)
     }
 }
 
 fun referToAliasedFunctionType(x: Any?) {
     contract {
-        returns() implies (x is FunctionalType)
+        returns() implies (x is <!CANNOT_CHECK_FOR_ERASED!>FunctionalType<!>)
     }
 }
 

compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/contractWithSubstitution.fir.kt

@@ -12,13 +12,13 @@ abstract class Base<T> {
 
     @OptIn(ExperimentalContracts::class)
     fun checkIsT(s: Any?): Boolean {
-        contract { <!ERROR_IN_CONTRACT_DESCRIPTION!>returns(true) implies (s is T)<!> }
+        contract { <!ERROR_IN_CONTRACT_DESCRIPTION!>returns(true) implies (s is <!CANNOT_CHECK_FOR_ERASED!>T<!>)<!> }
         return false
     }
 
     @OptIn(ExperimentalContracts::class)
     fun <R> checkIsOwnerR(s: Any?): Boolean {
-        contract { <!ERROR_IN_CONTRACT_DESCRIPTION!>returns(true) implies (s is R)<!> }
+        contract { <!ERROR_IN_CONTRACT_DESCRIPTION!>returns(true) implies (s is <!CANNOT_CHECK_FOR_ERASED!>R<!>)<!> }
         return false
     }