From 7ea1700b78974d0d372b780770ebfb83fc2e8352 Mon Sep 17 00:00:00 2001
From: Toshiaki Kameyama <kmymtsak@gmail.com>
Date: Tue, 23 Jun 2020 11:58:01 +0900
Subject: [PATCH] Convert lambda to reference: support generic function call

#KT-14578 Fixed
#KT-14395 Fixed
---
 .../ConvertLambdaToReferenceIntention.kt          | 12 ++++++++++--
 .../convertLambdaToReference/generic2.kt          |  6 ++++++
 .../convertLambdaToReference/generic2.kt.after    |  6 ++++++
 .../convertLambdaToReference/generic3.kt          |  8 ++++++++
 .../convertLambdaToReference/generic3.kt.after    |  8 ++++++++
 .../convertLambdaToReference/generic4.kt          |  4 ++++
 .../convertLambdaToReference/generic4.kt.after    |  4 ++++
 .../idea/intentions/IntentionTestGenerated.java   | 15 +++++++++++++++
 8 files changed, 61 insertions(+), 2 deletions(-)
 create mode 100644 idea/testData/intentions/convertLambdaToReference/generic2.kt
 create mode 100644 idea/testData/intentions/convertLambdaToReference/generic2.kt.after
 create mode 100644 idea/testData/intentions/convertLambdaToReference/generic3.kt
 create mode 100644 idea/testData/intentions/convertLambdaToReference/generic3.kt.after
 create mode 100644 idea/testData/intentions/convertLambdaToReference/generic4.kt
 create mode 100644 idea/testData/intentions/convertLambdaToReference/generic4.kt.after

diff --git a/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertLambdaToReferenceIntention.kt b/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertLambdaToReferenceIntention.kt
index ee5ecf1a7ab..b8b6a2b5007 100644
--- a/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertLambdaToReferenceIntention.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertLambdaToReferenceIntention.kt
@@ -88,7 +88,7 @@ open class ConvertLambdaToReferenceIntention(textGetter: () -> String) : SelfTar
         ) return false
 
         // No references with type parameters
-        if (calleeDescriptor.typeParameters.isNotEmpty()) return false
+        if (calleeDescriptor.typeParameters.isNotEmpty() && lambdaExpression.parentValueArgument() == null) return false
         // No references to Java synthetic properties
         if (calleeDescriptor is SyntheticJavaPropertyDescriptor) return false
 
@@ -237,6 +237,12 @@ open class ConvertLambdaToReferenceIntention(textGetter: () -> String) : SelfTar
                 }
                 lambdaArgument.delete()
             }
+
+            outerCallExpression.typeArgumentList?.let {
+                if (RemoveExplicitTypeArgumentsIntention.isApplicableTo(it, approximateFlexible = false)) {
+                    it.delete()
+                }
+            }
         }
     }
 
@@ -257,7 +263,9 @@ open class ConvertLambdaToReferenceIntention(textGetter: () -> String) : SelfTar
         val calledFunctionInLambda = lambda.singleStatementOrNull()
             ?.getResolvedCall(context)?.resultingDescriptor as? FunctionDescriptor ?: return
         val overloadedFunctions = calledFunctionInLambda.overloadedFunctions()
-        if (overloadedFunctions.count { it.valueParameters.size == calledFunctionInLambda.valueParameters.size } < 2) return
+        if (overloadedFunctions.count { it.valueParameters.size == calledFunctionInLambda.valueParameters.size } < 2
+            && calledFunctionInLambda.typeParameters.isEmpty()
+        ) return
 
         if (InsertExplicitTypeArgumentsIntention.isApplicableTo(this, context)) {
             InsertExplicitTypeArgumentsIntention.applyTo(this)
diff --git a/idea/testData/intentions/convertLambdaToReference/generic2.kt b/idea/testData/intentions/convertLambdaToReference/generic2.kt
new file mode 100644
index 00000000000..05e8308901e
--- /dev/null
+++ b/idea/testData/intentions/convertLambdaToReference/generic2.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+fun <T> foo(i: Int): T? = null
+
+fun test(list: List<Int>) {
+    list.mapNotNull <caret>{ foo<String>(it) }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/convertLambdaToReference/generic2.kt.after b/idea/testData/intentions/convertLambdaToReference/generic2.kt.after
new file mode 100644
index 00000000000..c94ec089480
--- /dev/null
+++ b/idea/testData/intentions/convertLambdaToReference/generic2.kt.after
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+fun <T> foo(i: Int): T? = null
+
+fun test(list: List<Int>) {
+    list.mapNotNull<Int, String>(::foo)
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/convertLambdaToReference/generic3.kt b/idea/testData/intentions/convertLambdaToReference/generic3.kt
new file mode 100644
index 00000000000..d7424173fa8
--- /dev/null
+++ b/idea/testData/intentions/convertLambdaToReference/generic3.kt
@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+interface CD
+
+fun <D : CD> D.foo(): D? = null
+
+fun test(x: List<CD>) {
+    x.mapNotNull <caret>{ it.foo() }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/convertLambdaToReference/generic3.kt.after b/idea/testData/intentions/convertLambdaToReference/generic3.kt.after
new file mode 100644
index 00000000000..ae1d640543d
--- /dev/null
+++ b/idea/testData/intentions/convertLambdaToReference/generic3.kt.after
@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+interface CD
+
+fun <D : CD> D.foo(): D? = null
+
+fun test(x: List<CD>) {
+    x.mapNotNull(CD::foo)
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/convertLambdaToReference/generic4.kt b/idea/testData/intentions/convertLambdaToReference/generic4.kt
new file mode 100644
index 00000000000..56dc4477189
--- /dev/null
+++ b/idea/testData/intentions/convertLambdaToReference/generic4.kt
@@ -0,0 +1,4 @@
+// WITH_RUNTIME
+fun test() {
+    listOf(listOf(1)).filter <caret>{ it.isNotEmpty() }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/convertLambdaToReference/generic4.kt.after b/idea/testData/intentions/convertLambdaToReference/generic4.kt.after
new file mode 100644
index 00000000000..05393768608
--- /dev/null
+++ b/idea/testData/intentions/convertLambdaToReference/generic4.kt.after
@@ -0,0 +1,4 @@
+// WITH_RUNTIME
+fun test() {
+    listOf(listOf(1)).filter(List<Int>::isNotEmpty)
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
index 535c5727b0a..f3ac1f62444 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
@@ -5095,6 +5095,21 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             runTest("idea/testData/intentions/convertLambdaToReference/generic.kt");
         }
 
+        @TestMetadata("generic2.kt")
+        public void testGeneric2() throws Exception {
+            runTest("idea/testData/intentions/convertLambdaToReference/generic2.kt");
+        }
+
+        @TestMetadata("generic3.kt")
+        public void testGeneric3() throws Exception {
+            runTest("idea/testData/intentions/convertLambdaToReference/generic3.kt");
+        }
+
+        @TestMetadata("generic4.kt")
+        public void testGeneric4() throws Exception {
+            runTest("idea/testData/intentions/convertLambdaToReference/generic4.kt");
+        }
+
         @TestMetadata("globalProperty.kt")
         public void testGlobalProperty() throws Exception {
             runTest("idea/testData/intentions/convertLambdaToReference/globalProperty.kt");