ExpressionUtils#isVoidContext updated for Java 12 (also for expression lists in for update)

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/ExpressionUtils.java

@@ -1341,13 +1341,24 @@ public class ExpressionUtils {
   /**
    * Returns true if expression is evaluated in void context (i.e. its return value is not used)
    * @param expression expression to check
-   * @return true if expression is evaluated in void context. More precisely if its parent is expression statement or lambda with void SAM
+   * @return true if expression is evaluated in void context.
    */
   public static boolean isVoidContext(PsiExpression expression) {
     PsiElement element = PsiUtil.skipParenthesizedExprUp(expression.getParent());
-    return element instanceof PsiExpressionStatement ||
-           (element instanceof PsiLambdaExpression &&
-            PsiType.VOID.equals(LambdaUtil.getFunctionalInterfaceReturnType((PsiLambdaExpression)element)));
+    if (element instanceof PsiExpressionStatement) {
+      if (element.getParent() instanceof PsiSwitchLabeledRuleStatement) {
+        PsiSwitchBlock block = ((PsiSwitchLabeledRuleStatement)element.getParent()).getEnclosingSwitchBlock();
+        return !(block instanceof PsiSwitchExpression);
+      }
+      return true;
+    }
+    if (element instanceof PsiExpressionList && element.getParent() instanceof PsiExpressionListStatement) {
+      return true;
+    }
+    if (element instanceof PsiLambdaExpression) {
+      if (PsiType.VOID.equals(LambdaUtil.getFunctionalInterfaceReturnType((PsiLambdaExpression)element))) return true;
+    }
+    return false;
   }
 
   /**

plugins/InspectionGadgets/testsrc/com/siyeh/ig/bugs/IgnoreResultOfCallInspectionTest.groovy

@@ -32,7 +32,7 @@ class IgnoreResultOfCallInspectionTest extends LightInspectionTestCase {
   @NotNull
   @Override
   protected LightProjectDescriptor getProjectDescriptor() {
-    return JAVA_8
+    return JAVA_12
   }
 
   @Override
@@ -344,6 +344,24 @@ public static int atLeast(int min, int actual, String varName) {
 
     return new byte[length];
   }
+}"""
+  }
+  
+  void testInForExpressionList() {
+    doTest """class X {
+  void test(String s) {
+    for(int i=0; i<10; i++, s./*Result of 'String.trim()' is ignored*/trim/**/()) {}
+  }
+}"""
+  }
+
+  void testInSwitchExpression() {
+    doTest """class X {
+  String test(String s) {
+    return switch(s) {
+      default -> s.trim();
+    };
+  }
 }"""
   }
 }