CharsetObjectCanBeUsedInspection: remove qualifier in static import

Fixes IDEA-193573 IDEA doesn't recornize static import on replacing by StandardCharsets

java/java-impl/src/com/intellij/codeInspection/CharsetObjectCanBeUsedInspection.java

@@ -5,6 +5,7 @@ import com.intellij.codeInsight.ExceptionUtil;
 import com.intellij.codeInsight.daemon.impl.quickfix.DeleteCatchFix;
 import com.intellij.codeInsight.daemon.impl.quickfix.DeleteMultiCatchFix;
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
 import com.intellij.psi.codeStyle.JavaCodeStyleManager;
 import com.intellij.psi.util.PsiTreeUtil;
@@ -13,6 +14,7 @@ import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
 import com.siyeh.ig.psiutils.CommentTracker;
 import com.siyeh.ig.psiutils.ExpressionUtils;
+import com.siyeh.ig.psiutils.ImportUtils;
 import one.util.streamex.StreamEx;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.Nls;
@@ -230,8 +232,17 @@ public class CharsetObjectCanBeUsedInspection extends AbstractBaseJavaLocalInspe
       PsiElement anchor = PsiTreeUtil.getParentOfType(expression, PsiCallExpression.class);
       if (anchor == null) return;
       CommentTracker ct = new CommentTracker();
-      JavaCodeStyleManager.getInstance(project)
-                          .shortenClassReferences(ct.replaceAndRestoreComments(expression, "java.nio.charset." + myConstantName));
+      String replacement = "java.nio.charset." + myConstantName;
+      PsiReferenceExpression ref = (PsiReferenceExpression)ct.replaceAndRestoreComments(expression, replacement);
+      PsiField field = ObjectUtils.tryCast(ref.resolve(), PsiField.class);
+      PsiExpression qualifier = ref.getQualifierExpression();
+      if (field != null && qualifier != null && ImportUtils.isStaticallyImported(field, ref)) {
+        PsiResolveHelper resolveHelper = JavaPsiFacade.getInstance(project).getResolveHelper();
+        if (field.equals(resolveHelper.resolveAccessibleReferencedVariable(StringUtil.getShortName(myConstantName), ref))) {
+          qualifier.delete();
+        }
+      }
+      JavaCodeStyleManager.getInstance(project).shortenClassReferences(ref);
       while (true) {
         PsiTryStatement tryStatement =
           PsiTreeUtil.getParentOfType(anchor, PsiTryStatement.class, true, PsiMember.class, PsiLambdaExpression.class);

java/java-tests/testData/inspection/charsetObjectCanBeUsed/afterStringRemoveQualifier.java

@@ -0,0 +1,10 @@
+// "Replace with 'StandardCharsets.UTF_8'" "true"
+import static java.nio.charset.StandardCharsets.*;
+
+class Test {
+  void test(byte[] bytes) throws Exception {
+    String string = new String(bytes, UTF_8);
+    System.out.println(string);
+    string.getBytes(UTF_8);
+  }
+}

java/java-tests/testData/inspection/charsetObjectCanBeUsed/afterStringRemoveQualifierConflict.java

@@ -0,0 +1,13 @@
+// "Replace with 'StandardCharsets.UTF_8'" "true"
+import java.nio.charset.StandardCharsets;
+
+import static java.nio.charset.StandardCharsets.*;
+
+class Test {
+  void test(byte[] bytes) throws Exception {
+    int UTF_8 = 1;
+    String string = new String(bytes, StandardCharsets.UTF_8);
+    System.out.println(string);
+    string.getBytes(UTF_16);
+  }
+}

java/java-tests/testData/inspection/charsetObjectCanBeUsed/beforeStringRemoveQualifier.java

@@ -0,0 +1,10 @@
+// "Replace with 'StandardCharsets.UTF_8'" "true"
+import static java.nio.charset.StandardCharsets.*;
+
+class Test {
+  void test(byte[] bytes) throws Exception {
+    String string = new String(bytes, "UTF<caret>-8");
+    System.out.println(string);
+    string.getBytes(UTF_8);
+  }
+}

java/java-tests/testData/inspection/charsetObjectCanBeUsed/beforeStringRemoveQualifierConflict.java

@@ -0,0 +1,11 @@
+// "Replace with 'StandardCharsets.UTF_8'" "true"
+import static java.nio.charset.StandardCharsets.*;
+
+class Test {
+  void test(byte[] bytes) throws Exception {
+    int UTF_8 = 1;
+    String string = new String(bytes, "UTF<caret>-8");
+    System.out.println(string);
+    string.getBytes(UTF_16);
+  }
+}