Allow only one invoke to be a target for smart step into (KT-18632)

It's difficult to distinguish such calls reliably in debug session

 #KT-18632 Fixed

idea/src/org/jetbrains/kotlin/idea/debugger/stepping/KotlinBasicStepMethodFilter.kt

@@ -72,12 +72,14 @@ class KotlinBasicStepMethodFilter(
         if (currentDescriptor !is CallableMemberDescriptor) return false
         if (currentDescriptor.kind != DECLARATION) return false
 
-        if (compareDescriptors(currentDescriptor, targetDescriptor)) return true
-
-        if (targetDescriptor is FunctionInvokeDescriptor && currentDescriptor is FunctionDescriptor) {
-            return isCompatibleSignatures(targetDescriptor, currentDescriptor)
+        if (targetDescriptor is FunctionInvokeDescriptor) {
+            // There can be only one 'invoke' target at the moment so consider position as expected.
+            // Descriptors can be not-equal, say when parameter has type `(T) -> T` and lambda is `Int.() -> Int`.
+            return true
         }
 
+        if (compareDescriptors(currentDescriptor, targetDescriptor)) return true
+
         // We should stop if current descriptor overrides the target one or some base descriptor of target
         // (if target descriptor is delegation or fake override)
 
@@ -100,24 +102,4 @@ class KotlinBasicStepMethodFilter(
 
 private fun compareDescriptors(d1: DeclarationDescriptor, d2: DeclarationDescriptor): Boolean {
     return d1 == d2 || d1.original == d2.original
-}
-
-private fun isCompatibleSignatures(target: FunctionDescriptor, current: FunctionDescriptor): Boolean {
-    // A very primitive approximation
-    if (target.valueParameters.size != current.valueParameters.size) {
-        return false
-    }
-
-    if (target.returnType != current.returnType) {
-        return false
-    }
-
-    for ((i, targetParam) in target.valueParameters.withIndex()) {
-        val currentParam = current.valueParameters[i]
-        if (targetParam.type != currentParam.type) {
-            return false
-        }
-    }
-
-    return true
 }

idea/src/org/jetbrains/kotlin/idea/debugger/stepping/KotlinMethodSmartStepIntoTarget.kt

@@ -3,6 +3,7 @@ package org.jetbrains.kotlin.idea.debugger.stepping
 import com.intellij.debugger.actions.SmartStepTarget
 import com.intellij.psi.PsiElement
 import com.intellij.util.Range
+import org.jetbrains.kotlin.builtins.functions.FunctionInvokeDescriptor
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.idea.KotlinIcons
@@ -43,8 +44,19 @@ class KotlinMethodSmartStepTarget(
 
         if (other == null || other !is KotlinMethodSmartStepTarget) return false
 
+        if (descriptor is FunctionInvokeDescriptor && other.descriptor is FunctionInvokeDescriptor) {
+            // Don't allow to choose several invoke targets in smart step into as we can't distinguish them reliably during debug
+            return true
+        }
+
         return descriptor == other.descriptor
     }
 
-    override fun hashCode() = descriptor.hashCode()
+    override fun hashCode(): Int {
+        if (descriptor is FunctionInvokeDescriptor) {
+            // Predefined value to make all FunctionInvokeDescriptor targets equal
+            return 42
+        }
+        return descriptor.hashCode()
+    }
 }

idea/testData/debugger/tinyApp/src/stepping/custom/smartStepIntoToLambdaParameter.kt

@@ -14,11 +14,12 @@ fun defaultParameter(f: (String) -> Int = { it.toInt() }) {
     f("12")
 }
 
-fun badSignatureIsSkipped(f: (String) -> Int = { it.toInt() }, paramFun: (Int) -> Int) {
+// Minor bug is here. During selection paramFun() is shown as a target, but f is called instead.
+fun firstInvokeIsCalled(f: (String) -> Int = { it.toInt() }, paramFun: (Int) -> Int) {
     // SMART_STEP_INTO_BY_INDEX: 0
     // RESUME: 1
     //Breakpoint!
-    paramFun(f("12"))
+    paramFun(f("12")) + ii()
 }
 
 fun nonDefaultWithAnonymousFun(paramFun: (Int) -> Int) {
@@ -35,16 +36,28 @@ fun withExtensionParameters(paramFun: Int.() -> Int) {
     12.paramFun()
 }
 
+fun <T> genericSignatureAndExtensionArgument(v: T, paramFun: (T) -> T) {
+    // SMART_STEP_INTO_BY_INDEX: 0
+    // RESUME: 1
+    //Breakpoint!
+    paramFun(v)
+}
+
 fun main(args: Array<String>) {
-    val localFun : (Int) -> Int = { it + 1 }
+    val localFun: (Int) -> Int = { it + 1 }
 
     nonDefaultParameter(localFun)
 
     defaultParameter()
 
-    badSignatureIsSkipped { it + 1 }
+    firstInvokeIsCalled { it + 1 }
 
     nonDefaultWithAnonymousFun(fun (i: Int): Int { return i })
 
     withExtensionParameters { this }
-}
+
+    val ext: Int.() -> Int = { this }
+    genericSignatureAndExtensionArgument(15, ext)
+}
+
+fun ii() = 12

idea/testData/debugger/tinyApp/src/stepping/custom/smartStepIntoToLambdaParameter.out

@@ -1,20 +1,23 @@
 LineBreakpoint created at smartStepIntoToLambdaParameter.kt:7
 LineBreakpoint created at smartStepIntoToLambdaParameter.kt:14
-LineBreakpoint created at smartStepIntoToLambdaParameter.kt:21
-LineBreakpoint created at smartStepIntoToLambdaParameter.kt:28
-LineBreakpoint created at smartStepIntoToLambdaParameter.kt:35
+LineBreakpoint created at smartStepIntoToLambdaParameter.kt:22
+LineBreakpoint created at smartStepIntoToLambdaParameter.kt:29
+LineBreakpoint created at smartStepIntoToLambdaParameter.kt:36
+LineBreakpoint created at smartStepIntoToLambdaParameter.kt:43
 Run Java
 Connected to the target VM
 smartStepIntoToLambdaParameter.kt:7
-smartStepIntoToLambdaParameter.kt:39
+smartStepIntoToLambdaParameter.kt:47
 smartStepIntoToLambdaParameter.kt:14
 smartStepIntoToLambdaParameter.kt:10
-smartStepIntoToLambdaParameter.kt:21
-smartStepIntoToLambdaParameter.kt:45
-smartStepIntoToLambdaParameter.kt:28
-smartStepIntoToLambdaParameter.kt:47
-smartStepIntoToLambdaParameter.kt:35
-smartStepIntoToLambdaParameter.kt:49
+smartStepIntoToLambdaParameter.kt:22
+smartStepIntoToLambdaParameter.kt:18
+smartStepIntoToLambdaParameter.kt:29
+smartStepIntoToLambdaParameter.kt:55
+smartStepIntoToLambdaParameter.kt:36
+smartStepIntoToLambdaParameter.kt:57
+smartStepIntoToLambdaParameter.kt:43
+smartStepIntoToLambdaParameter.kt:59
 Disconnected from the target VM
 
 Process finished with exit code 0