Report UNUSED_EXPRESSION on anonymous functions

Changelog.md

@@ -9,6 +9,7 @@
 - Show only changed files in notification "Kotlin not configured"
 - Configure Kotlin: restore all changed files in undo action
 - Enable precise incremental compilation by default
+- Report warning about unused anonymous functions
 
 ### JVM
 - Remove the compiler option "Xmultifile-facades-open"

compiler/frontend/src/org/jetbrains/kotlin/cfg/pseudocode/pseudocodeUtils.kt

@@ -260,6 +260,7 @@ fun Instruction.calcSideEffectFree(): Boolean {
                 }
 
                 else -> when (element) {
+                    is KtNamedFunction -> element.name == null
                     is KtConstantExpression, is KtLambdaExpression, is KtStringTemplateExpression -> true
                     else -> false
                 }

compiler/testData/diagnostics/tests/declarationChecks/FunctionWithMissingNames.kt

@@ -18,9 +18,9 @@ class Outer {
 }
 
 fun outerFun() {
-    fun () {}
-    fun B.() {}
+    <!UNUSED_EXPRESSION!>fun () {}<!>
+    <!UNUSED_EXPRESSION!>fun B.() {}<!>
 
-    @a fun () {}
-    fun @a A.() {}
+    <!UNUSED_EXPRESSION!>@a fun () {}<!>
+    <!UNUSED_EXPRESSION!>fun @a A.() {}<!>
 }

compiler/testData/diagnostics/tests/declarationChecks/anonymousFunUnusedLastExpressionInBlock.kt

@@ -1,21 +1,21 @@
 fun unusedExpressions() {
     if (1 == 1)
-        fun(): Int {return 1}
+        <!UNUSED_EXPRESSION!>fun(): Int {return 1}<!>
     else
-        fun() = 1
+        <!UNUSED_EXPRESSION!>fun() = 1<!>
 
     if (1 == 1) {
-        fun(): Int {
+        <!UNUSED_EXPRESSION!>fun(): Int {
             return 1
-        }
+        }<!>
     }
     else
-        fun() = 1
+        <!UNUSED_EXPRESSION!>fun() = 1<!>
 
     when (1) {
-        0 -> fun(): Int {return 1}
-        else -> fun() = 1
+        0 -> <!UNUSED_EXPRESSION!>fun(): Int {return 1}<!>
+        else -> <!UNUSED_EXPRESSION!>fun() = 1<!>
     }
 
-    fun() = 1
+    <!UNUSED_EXPRESSION!>fun() = 1<!>
 }

compiler/testData/diagnostics/tests/duplicateJvmSignature/missingNames.kt

@@ -58,11 +58,11 @@ class Outer {
 }
 
 fun outerFun() {
-    fun () {
+    <!UNUSED_EXPRESSION!>fun () {
 
-    }
-    fun () {
+    }<!>
+    <!UNUSED_EXPRESSION!>fun () {
 
-    }
+    }<!>
 }
 

compiler/testData/diagnostics/tests/regressions/kt306.kt

@@ -1,17 +1,17 @@
 // KT-306 Ambiguity when different this's have same-looking functions
 
 fun test() {
-    (fun Foo.() {
+    (<!UNUSED_EXPRESSION!>fun Foo.() {
         bar()
-        (fun Barr.() {
+        (<!UNUSED_EXPRESSION!>fun Barr.() {
             this.bar()
             bar()
-        })
-    })
-    (fun Barr.() {
+        }<!>)
+    }<!>)
+    (<!UNUSED_EXPRESSION!>fun Barr.() {
         this.bar()
         bar()
-    })
+    }<!>)
 }
 
 class Foo {