IDEA-177741 Annotation folding does not fold parameter annotations

java/java-psi-impl/src/com/intellij/codeInsight/folding/impl/JavaFoldingBuilderBase.java

@@ -39,7 +39,10 @@ import com.intellij.psi.impl.source.tree.JavaDocElementType;
 import com.intellij.psi.impl.source.tree.JavaElementType;
 import com.intellij.psi.javadoc.PsiDocComment;
 import com.intellij.psi.tree.IElementType;
-import com.intellij.psi.util.*;
+import com.intellij.psi.util.PropertyUtilBase;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.psi.util.PsiUtil;
+import com.intellij.psi.util.PsiUtilCore;
 import com.intellij.util.text.CharArrayUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -549,6 +552,10 @@ public abstract class JavaFoldingBuilderBase extends CustomFoldingBuilder implem
           addDocCommentToFold(list, document, method);
         }
 
+        for (PsiParameter parameter : method.getParameterList().getParameters()) {
+          addAnnotationsToFold(parameter.getModifierList(), list, document);
+        }
+
         PsiCodeBlock body = method.getBody();
         if (body != null && !oneLiner) {
           addCodeBlockFolds(body, list, processedComments, document, quick);

java/java-tests/testSrc/com/intellij/java/codeInsight/folding/JavaFolding8Test.groovy

@@ -91,4 +91,24 @@ class Test {
 
     assert foldingModel.getCollapsedRegionAtOffset(text.indexOf("System.out.println"))?.placeholderText == '{...}'
   }
+  
+  void "test parameter annotations"() {
+    configure """\
+class Some {
+    void m(@Anno("hello " +
+                 "world") int a,
+           @Anno("goodbye " +
+                 "world") int b) {}
+}
+
+@interface Anno { 
+    String value();
+}
+"""
+    assert myFixture.editor.foldingModel.allFoldRegions.toString() == 
+           '[FoldRegion -(11:141), placeholder=\'{...}\', ' +
+           'FoldRegion -(24:66), placeholder=\'@{...}\', ' +
+           'FoldRegion -(85:129), placeholder=\'@{...}\', ' +
+           'FoldRegion -(159:183), placeholder=\'{...}\']'
+  }
 }