IG: recognize when catch blocks containing a return statement are identical (IDEA-159182)

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/migration/TryWithIdenticalCatchesInspection.java

@@ -24,6 +24,8 @@ import com.intellij.psi.util.TypeConversionUtil;
 import com.intellij.refactoring.extractMethod.InputVariables;
 import com.intellij.refactoring.util.duplicates.DuplicatesFinder;
 import com.intellij.refactoring.util.duplicates.Match;
+import com.intellij.refactoring.util.duplicates.ReturnStatementReturnValue;
+import com.intellij.refactoring.util.duplicates.ReturnValue;
 import com.intellij.util.IncorrectOperationException;
 import com.siyeh.InspectionGadgetsBundle;
 import com.siyeh.ig.BaseInspection;
@@ -110,7 +112,11 @@ public class TryWithIdenticalCatchesInspection extends BaseInspection {
             continue;
           }
           final Match match = finder.isDuplicate(otherCatchBlock, true);
-          if (match == null || match.getReturnValue() != null) {
+          if (match == null) {
+            continue;
+          }
+          final ReturnValue returnValue = match.getReturnValue();
+          if (returnValue != null && !(returnValue instanceof ReturnStatementReturnValue)) {
             continue;
           }
           final List<PsiElement> parameterValues = match.getParameterValues(parameter);

plugins/InspectionGadgets/test/com/siyeh/igtest/errorhandling/try_identical_catches/TryIdenticalCatches.after.java

@@ -160,4 +160,17 @@ class TryIdenticalCatches {
 
   void foo() throws IOException {}
   private static final IOException INSTANCE = new IOException();
+
+  public boolean returning() {
+    try {
+      // work
+    }
+    catch(NumberFormatException e) {
+      return true;
+    }
+    catch(RuntimeException e) {
+      return true;
+    }
+    return false;
+  }
 }

plugins/InspectionGadgets/test/com/siyeh/igtest/errorhandling/try_identical_catches/TryIdenticalCatches.java

@@ -163,4 +163,17 @@ class TryIdenticalCatches {
 
   void foo() throws IOException {}
   private static final IOException INSTANCE = new IOException();
+
+  public boolean returning() {
+    try {
+      // work
+    }
+    catch(NumberFormatException e) {
+      return true;
+    }
+    <warning descr="'catch' branch identical to 'NumberFormatException' branch">catch(RuntimeException e)</warning> {
+      return true;
+    }
+    return false;
+  }
 }