Prohibit declaring multiple callsInPlace contract on same lambda.

#KT-26150 fixed

compiler/frontend/src/org/jetbrains/kotlin/contracts/parsing/PsiContractParserDispatcher.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.contracts.parsing
 
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.contracts.description.BooleanExpression
+import org.jetbrains.kotlin.contracts.description.CallsEffectDeclaration
 import org.jetbrains.kotlin.contracts.description.ContractDescription
 import org.jetbrains.kotlin.contracts.description.EffectDeclaration
 import org.jetbrains.kotlin.contracts.description.expressions.BooleanVariableReference
@@ -69,8 +70,9 @@ internal class PsiContractParserDispatcher(
             return null
         }
 
-        val effects = lambda.bodyExpression?.statements?.mapNotNull { parseEffect(it) } ?: return null
-
+        val effectsWithExpression = lambda.bodyExpression?.statements?.map { parseEffect(it) to it } ?: return null
+        checkDuplicatedCallsEffectsAndReport(effectsWithExpression)
+        val effects = effectsWithExpression.mapNotNull { it.first }
         if (effects.isEmpty()) return null
 
         return ContractDescription(effects, callContext.functionDescriptor, storageManager)
@@ -92,6 +94,19 @@ internal class PsiContractParserDispatcher(
         return parser.tryParseEffect(expression)
     }
 
+    private fun checkDuplicatedCallsEffectsAndReport(effects: List<Pair<EffectDeclaration?, KtExpression>>) {
+        val descriptorsWithCallsEffect = mutableSetOf<ParameterDescriptor>()
+        for ((effect, expression) in effects) {
+            if (effect !is CallsEffectDeclaration) continue
+            val descriptor = effect.variableReference.descriptor
+            if (descriptor in descriptorsWithCallsEffect) {
+                collector.badDescription("Duplicated contract for ${descriptor.name}. Only one `callsInPlace` contract per parameter is allowed.", expression)
+            } else {
+                descriptorsWithCallsEffect.add(descriptor)
+            }
+        }
+    }
+
     private fun isValidEffectDeclaration(expression: KtExpression): Boolean {
         if (expression !is KtCallExpression && expression !is KtBinaryExpression) {
             collector.badDescription("unexpected construction in contract description", expression)