Do not report "redundant suspend" on override / open #KT-21938 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantSuspendModifierInspection.kt

@@ -22,7 +22,9 @@ import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.idea.caches.resolve.analyzeFully
+import org.jetbrains.kotlin.idea.core.getModalityFromDescriptor
 import org.jetbrains.kotlin.idea.highlighter.hasSuspendCalls
 import org.jetbrains.kotlin.idea.project.languageVersionSettings
 import org.jetbrains.kotlin.idea.quickfix.RemoveModifierFix
@@ -31,6 +33,7 @@ import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtNamedFunction
 import org.jetbrains.kotlin.psi.KtVisitorVoid
 import org.jetbrains.kotlin.psi.psiUtil.anyDescendantOfType
+import org.jetbrains.kotlin.resolve.BindingContext
 
 class RedundantSuspendModifierInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
@@ -41,8 +44,11 @@ class RedundantSuspendModifierInspection : AbstractKotlinInspection() {
 
                 val suspendModifier = function.modifierList?.getModifier(KtTokens.SUSPEND_KEYWORD) ?: return
                 if (!function.hasBody()) return
+                if (function.hasModifier(KtTokens.OVERRIDE_KEYWORD)) return
 
                 val context = function.analyzeFully()
+                val descriptor = context[BindingContext.FUNCTION, function] ?: return
+                if (descriptor.modality == Modality.OPEN) return
 
                 if (function.anyDescendantOfType<KtExpression> { it.hasSuspendCalls(context) }) {
                     return

idea/testData/inspections/redundantSuspendModifier/operators.kt

@@ -40,4 +40,25 @@ class C(val x: Int, val y: Int) {
 // Not redundant
 suspend fun foo(c1: C, c2: C): Int {
     return c1() + c2()
+}
+
+interface C {
+    // Not redundant
+    suspend fun foo()
+}
+
+class D : C {
+    // Not redundant
+    override suspend fun foo() {
+
+    }
+}
+
+open class E {
+    // Not redundant
+    open suspend fun bar() {
+
+    }
+    // Not redundant
+    abstract suspend fun baz()
 }

idea/testData/inspectionsLocal/redundantSuspend/override.kt

@@ -0,0 +1,10 @@
+// PROBLEM: none
+
+interface I {
+    suspend fun f()
+}
+
+class C : I {
+    override <caret>suspend fun f() {
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -2885,6 +2885,12 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("override.kt")
+        public void testOverride() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/redundantSuspend/override.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("setterDelegate.kt")
         public void testSetterDelegate() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/redundantSuspend/setterDelegate.kt");