Introduce "redundant suspend" inspection #KT-19103 Fixed

idea/testData/inspections/redundantSuspendModifier/inspectionData/expected.xml

@@ -0,0 +1,67 @@
+<problems>
+    <problem>
+        <file>test.kt</file>
+        <line>13</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>33</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>35</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>40</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+    <!-- FIXME: Incorrect problem -->
+    <problem>
+        <file>test.kt</file>
+        <line>57</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+    <problem>
+        <file>operators.kt</file>
+        <line>5</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/operators.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+    <problem>
+        <file>operators.kt</file>
+        <line>23</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/operators.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+    <problem>
+        <file>operators.kt</file>
+        <line>37</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/operators.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'suspend' modifier</problem_class>
+        <description>Redundant 'suspend' modifier</description>
+    </problem>
+</problems>

idea/testData/inspections/redundantSuspendModifier/inspectionData/inspections.test

@@ -0,0 +1 @@
+// INSPECTION_CLASS: org.jetbrains.kotlin.idea.inspections.RedundantSuspendModifierInspection

idea/testData/inspections/redundantSuspendModifier/operators.kt

@@ -0,0 +1,43 @@
+// WITH_RUNTIME
+
+class A(val x: Int) {
+    // Redundant
+    suspend operator fun plus(a: A): A {
+        return A(x + a.x)
+    }
+}
+
+// Not redundant
+suspend fun foo(a1: A, a2: A): A {
+    return a1 + a2
+}
+// Not redundant
+suspend fun bar(a1: A, a2: A): A {
+    var result = a1
+    result += a2
+    return result
+}
+
+class B(var x: Int) {
+    // Redundant
+    suspend operator fun minusAssign(b: B) {
+        x -= b.x
+    }
+}
+
+// Not redundant
+suspend fun foo(b1: B, b2: B): B {
+    val result = b1
+    result -= b2
+    return result
+}
+
+class C(val x: Int, val y: Int) {
+    // Redundant
+    suspend operator fun invoke() = x + y
+}
+
+// Not redundant
+suspend fun foo(c1: C, c2: C): Int {
+    return c1() + c2()
+}

idea/testData/inspections/redundantSuspendModifier/test.kt

@@ -0,0 +1,69 @@
+// WITH_RUNTIME
+
+fun coroutine(block: suspend () -> Unit) {}
+
+// Not redundant
+suspend fun rootSuspend() {
+    coroutine {
+        empty()
+    }
+}
+
+// Redundant
+suspend fun empty() {}
+
+suspend fun suspendUser() = rootSuspend() // not redundant
+
+open class My {
+    // Not redundant
+    open suspend fun baseSuspend() {
+        rootSuspend()
+    }
+}
+
+class Your : My() {
+    override fun baseSuspend() {
+
+    }
+}
+
+class SIterable {
+    operator fun iterator() = this
+    // Redundant
+    suspend operator fun hasNext(): Boolean = false
+    // Redundant
+    suspend operator fun next(): Int = 0
+}
+
+class SIterator {
+    // Redundant
+    suspend operator fun iterator() = this
+    operator fun hasNext(): Boolean = false
+    operator fun next(): Int = 0
+
+}
+
+// Not redundant
+suspend fun foo() {
+    val iterable = SIterable()
+    coroutine {
+        for (x in iterable) {
+            println(x)
+        }
+    }
+}
+
+// Not redundant
+suspend fun bar() {
+    val iterator = SIterator()
+    coroutine {
+        for (x in iterator) {
+            println(x)
+        }
+    }
+}
+
+interface Suspended {
+    // Not redundant
+    suspend fun bar()
+}