inline: do not delete call but warn when resulted expr is not a valid statement (IDEA-88886)

java/java-impl/src/com/intellij/refactoring/inline/InlineMethodProcessor.java

@@ -190,6 +190,21 @@ public class InlineMethodProcessor extends BaseRefactoringProcessor {
       }
     }
 
+    final PsiReturnStatement[] returnStatements = RefactoringUtil.findReturnStatements(myMethod);
+    for (PsiReturnStatement statement : returnStatements) {
+      PsiExpression value = statement.getReturnValue();
+      if (value != null && !(value instanceof PsiCallExpression)) {
+        for (UsageInfo info : usagesIn) {
+          PsiReference reference = info.getReference();
+          InlineUtil.TailCallType type = InlineUtil.getTailCallType(reference);
+          if (type == InlineUtil.TailCallType.Simple) {
+            conflicts.putValue(statement, "Inlined result won't be a valid statement");
+            break;
+          }
+        }
+      }
+    }
+
     addInaccessibleMemberConflicts(myMethod, usagesIn, new ReferencedElementsCollector(), conflicts);
 
     addInaccessibleSuperCallsConflicts(usagesIn, conflicts);
@@ -730,7 +745,7 @@ public class InlineMethodProcessor extends BaseRefactoringProcessor {
         if (returnValue == null) continue;
         PsiStatement statement;
         if (tailCallType == InlineUtil.TailCallType.Simple) {
-          if (returnValue instanceof PsiCallExpression) {
+          if (returnValue instanceof PsiExpression) {
             PsiExpressionStatement exprStatement = (PsiExpressionStatement) myFactory.createStatementFromText("a;", null);
             exprStatement.getExpression().replace(returnValue);
             returnStatement.getParent().addBefore(exprStatement, returnStatement);

java/java-tests/testData/refactoring/inlineMethod/NotAStatement.java

@@ -0,0 +1,26 @@
+class AAA {
+  void fff(Project myProject) {
+    ensureFilesWritable(myProject, new String[1]);
+  }
+
+  private boolean ensu<caret>reFilesWritable(final Project project, final String... strings) {
+    return !ensureFilesWritable(strings).hasReadonlyFiles();
+  }
+
+  private Status ensureFilesWritable(final String[] strings) {
+    return new Status(strings);
+  }
+
+  class Status {
+    public Status(final String[] strings) {
+      //To change body of created methods use File | Settings | File Templates.
+    }
+
+    boolean hasReadonlyFiles() {
+      return true;
+    }
+  }
+
+  class Project {
+  }
+}

java/java-tests/testData/refactoring/inlineMethod/TailCallSimple.java

@@ -7,6 +7,6 @@ class A {
     }
 
     public String method(boolean b) {
-        <caret>toInline(b);
+        return <caret>toInline(b);
     }
 }

java/java-tests/testData/refactoring/inlineMethod/TailCallSimple.java.after

@@ -2,7 +2,8 @@ class A {
 
     public String method(boolean b) {
         if (b) {
-            return;
+            return "b";
         }
+        return "a";
     }
 }

java/java-tests/testSrc/com/intellij/refactoring/inline/InlineMethodTest.java

@@ -185,12 +185,20 @@ public class InlineMethodTest extends LightRefactoringTestCase {
   }
 
   public void testMethodUsedInJavadoc() throws Exception {
+    doTestConflict("Inlined method is used in javadoc");
+  }
+
+  public void testNotAStatement() throws Exception {
+    doTestConflict("Inlined result won't be a valid statement");
+  }
+
+  private void doTestConflict(final String conflict) throws Exception {
     try {
       doTest();
       fail("Conflict was not detected");
     }
     catch (BaseRefactoringProcessor.ConflictsInTestsException e) {
-      assertEquals("Inlined method is used in javadoc", e.getMessage());
+      assertEquals(conflict, e.getMessage());
     }
   }