Completion auto-popup works at the start of function literal

idea/src/org/jetbrains/kotlin/idea/completion/KotlinCompletionCharFilter.kt

@@ -23,6 +23,10 @@ import org.jetbrains.kotlin.psi.JetFile
 import com.intellij.openapi.util.Key
 import com.intellij.codeInsight.completion.CompletionService
 import com.intellij.codeInsight.completion.CompletionProgressIndicator
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.psi.psiUtil.prevLeafSkipWhitespacesAndComments
+import org.jetbrains.kotlin.lexer.JetTokens
+import org.jetbrains.kotlin.psi.JetFunctionLiteral
 
 public class KotlinCompletionCharFilter() : CharFilter() {
     class object {
@@ -36,9 +40,19 @@ public class KotlinCompletionCharFilter() : CharFilter() {
         if (!lookup.isCompletion()) return null
         // it does not work in tests, so we use other way
 //        val isAutopopup = CompletionService.getCompletionService().getCurrentCompletion().isAutopopupCompletion()
-        val isAutopopup = (CompletionService.getCompletionService().getCurrentCompletion() as CompletionProgressIndicator).getParameters().getInvocationCount() == 0
+        val completionParameters = (CompletionService.getCompletionService().getCurrentCompletion() as CompletionProgressIndicator).getParameters()
+        val isAutopopup = completionParameters.getInvocationCount() == 0
 
-        if (Character.isJavaIdentifierPart(c) || c == ':' /* used in '::xxx'*/ || c == '@') {
+        if (Character.isJavaIdentifierPart(c) || c == '@') {
+            return CharFilter.Result.ADD_TO_PREFIX
+        }
+
+        // do not accept items by special chars in the very beginning of function literal where name of the first parameter can be
+        if (isAutopopup && !lookup.isSelectionTouched() && isInFunctionLiteralStart(completionParameters.getPosition())) {
+            return Result.HIDE_LOOKUP
+        }
+
+        if (c == ':' /* used in '::xxx'*/) {
             return CharFilter.Result.ADD_TO_PREFIX
         }
 
@@ -70,4 +84,14 @@ public class KotlinCompletionCharFilter() : CharFilter() {
             else -> CharFilter.Result.HIDE_LOOKUP
         }
     }
+
+    private fun isInFunctionLiteralStart(position: PsiElement): Boolean {
+        var prev = position.prevLeafSkipWhitespacesAndComments()
+        if (prev?.getNode()?.getElementType() == JetTokens.LPAR) {
+            prev = prev?.prevLeafSkipWhitespacesAndComments()
+        }
+        if (prev?.getNode()?.getElementType() != JetTokens.LBRACE) return false
+        val functionLiteral = prev!!.getParent() as? JetFunctionLiteral ?: return false
+        return functionLiteral.getLBrace() == prev
+    }
 }

idea/src/org/jetbrains/kotlin/idea/completion/KotlinCompletionContributor.kt

@@ -248,9 +248,6 @@ public class KotlinCompletionContributor : CompletionContributor() {
         // no auto-popup on typing after "val", "var" and "fun" because it's likely the name of the declaration which is being typed by user
         if (invocationCount == 0 && isInExtensionReceiver(position)) return true
 
-        // no auto-popup on typing in the very beginning of function literal where name of the first parameter can be
-        if (invocationCount == 0 && isInFunctionLiteralStart(position)) return true
-
         return false
     }
 
@@ -267,16 +264,6 @@ public class KotlinCompletionContributor : CompletionContributor() {
         }
     }
 
-    private fun isInFunctionLiteralStart(position: PsiElement): Boolean {
-        var prev = position.prevLeafSkipWhitespacesAndComments()
-        if (prev?.getNode()?.getElementType() == JetTokens.LPAR) {
-            prev = prev?.prevLeafSkipWhitespacesAndComments()
-        }
-        if (prev?.getNode()?.getElementType() != JetTokens.LBRACE) return false
-        val functionLiteral = prev!!.getParent() as? JetFunctionLiteral ?: return false
-        return functionLiteral.getLBrace() == prev
-    }
-
     private fun isAtEndOfLine(offset: Int, document: Document): Boolean {
         var i = offset
         val chars = document.getCharsSequence()

idea/testData/completion/basic/common/FunctionLiteralParameterName0.kt

@@ -3,4 +3,5 @@ fun bar() {
 }
 
 // INVOCATION_COUNT: 0
-// NUMBER: 0
+// EXIST: bar
+// EXIST: null

idea/testData/completion/basic/common/FunctionLiteralParameterName1.kt

@@ -3,4 +3,5 @@ fun bar() {
 }
 
 // INVOCATION_COUNT: 0
-// NUMBER: 0
+// EXIST: bar
+// EXIST: null

idea/testData/completion/basic/common/FunctionLiteralParameterName5.kt

@@ -5,4 +5,5 @@ fun bar() {
 }
 
 // INVOCATION_COUNT: 0
-// NUMBER: 0
+// EXIST: bar
+// EXIST: null

idea/testData/completion/handlers/charFilter/FunctionLiteralParameter1.kt

@@ -0,0 +1,9 @@
+fun foo(p: (String) -> Unit){}
+
+fun bar() {
+    foo { p<caret> }
+}
+
+// INVOCATION_COUNT: 0
+// ELEMENT: *
+// CHAR: ' '

idea/testData/completion/handlers/charFilter/FunctionLiteralParameter1.kt.after

@@ -0,0 +1,9 @@
+fun foo(p: (String) -> Unit){}
+
+fun bar() {
+    foo { p <caret> }
+}
+
+// INVOCATION_COUNT: 0
+// ELEMENT: *
+// CHAR: ' '

idea/testData/completion/handlers/charFilter/FunctionLiteralParameter2.kt

@@ -0,0 +1,9 @@
+fun foo(p: (String) -> Unit){}
+
+fun bar() {
+    foo { (p<caret> }
+}
+
+// INVOCATION_COUNT: 0
+// ELEMENT: *
+// CHAR: ':'

idea/testData/completion/handlers/charFilter/FunctionLiteralParameter2.kt.after

@@ -0,0 +1,9 @@
+fun foo(p: (String) -> Unit){}
+
+fun bar() {
+    foo { (p:<caret> }
+}
+
+// INVOCATION_COUNT: 0
+// ELEMENT: *
+// CHAR: ':'

idea/testData/completion/handlers/charFilter/FunctionLiteralParameter3.kt

@@ -0,0 +1,9 @@
+fun bar() {
+    val handler = { p<caret>
+        foo()
+    }
+}
+
+// INVOCATION_COUNT: 0
+// ELEMENT: *
+// CHAR: ' '

idea/testData/completion/handlers/charFilter/FunctionLiteralParameter3.kt.after

@@ -0,0 +1,9 @@
+fun bar() {
+    val handler = { p <caret>
+        foo()
+    }
+}
+
+// INVOCATION_COUNT: 0
+// ELEMENT: *
+// CHAR: ' '

idea/tests/org/jetbrains/kotlin/completion/handlers/CompletionCharFilterTestGenerated.java

@@ -126,6 +126,24 @@ public class CompletionCharFilterTestGenerated extends AbstractCompletionCharFil
         doTest(fileName);
     }
 
+    @TestMetadata("FunctionLiteralParameter1.kt")
+    public void testFunctionLiteralParameter1() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/handlers/charFilter/FunctionLiteralParameter1.kt");
+        doTest(fileName);
+    }
+
+    @TestMetadata("FunctionLiteralParameter2.kt")
+    public void testFunctionLiteralParameter2() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/handlers/charFilter/FunctionLiteralParameter2.kt");
+        doTest(fileName);
+    }
+
+    @TestMetadata("FunctionLiteralParameter3.kt")
+    public void testFunctionLiteralParameter3() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/handlers/charFilter/FunctionLiteralParameter3.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("FunctionWithLambdaArg1.kt")
     public void testFunctionWithLambdaArg1() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/handlers/charFilter/FunctionWithLambdaArg1.kt");