PY-85080 Add quick-fix to remove unused Type Parameters

GitOrigin-RevId: cbb9b8136d07350075a9af8b4bc5aaa8891edd73

python/python-psi-impl/resources/messages/PyPsiBundle.properties

@@ -374,6 +374,7 @@ QFIX.NAME.add.field.to.class=Add field to class
 QFIX.add.field.to.class=Add field ''{0}'' to class {1}
 QFIX.add.field.to.class.popup.content.added.init=Added a __init__ to class <code>{0}</code><br/>to accommodate new field <code>{1}</code>
 QFIX.NAME.remove.parameter=Remove parameter
+QFIX.NAME.remove.type.parameter=Remove type parameter
 QFIX.NAME.rename.parameter=Rename parameter
 QFIX.rename.parameter=Rename to ''{0}''
 QFIX.NAME.remove.statement=Remove statement

python/python-psi-impl/src/com/jetbrains/python/inspections/quickfix/PyRemoveTypeParameterQuickFix.kt

@@ -0,0 +1,49 @@
+package com.jetbrains.python.inspections.quickfix
+
+import com.intellij.modcommand.ModPsiUpdater
+import com.intellij.modcommand.PsiUpdateModCommandQuickFix
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiWhiteSpace
+import com.intellij.psi.util.PsiTreeUtil
+import com.jetbrains.python.PyPsiBundle
+import com.jetbrains.python.PyTokenTypes
+import com.jetbrains.python.psi.PyElement
+import com.jetbrains.python.psi.PyTypeParameter
+import com.jetbrains.python.psi.PyTypeParameterList
+
+/**
+ * Removes a single type parameter from a type parameter list.
+ * If the list becomes empty, removes the brackets as well.
+ */
+class PyRemoveTypeParameterQuickFix : PsiUpdateModCommandQuickFix() {
+  override fun getFamilyName(): String = PyPsiBundle.message("QFIX.NAME.remove.type.parameter")
+
+  override fun applyFix(project: Project, element: PsiElement, updater: ModPsiUpdater) {
+    val typeParameter = PsiTreeUtil.getParentOfType(element, PyTypeParameter::class.java, false) ?: return
+    val list = PsiTreeUtil.getParentOfType(typeParameter, PyTypeParameterList::class.java, false) ?: return
+
+    var prev: PsiElement? = typeParameter.prevSibling
+    var next: PsiElement? = typeParameter.nextSibling
+
+    if (prev is PsiWhiteSpace) prev = prev.prevSibling
+    if (next is PsiWhiteSpace) next = next.nextSibling
+
+    if (prev != null && prev.node.elementType == PyTokenTypes.COMMA) {
+      prev.delete()
+      val afterComma = typeParameter.prevSibling
+      if (afterComma is PsiWhiteSpace) afterComma.delete()
+    }
+    else if (next != null && next.node.elementType == PyTokenTypes.COMMA) {
+      val ws = next.nextSibling
+      next.delete()
+      if (ws is PsiWhiteSpace) ws.delete()
+    }
+
+    typeParameter.delete()
+
+    if (list.typeParameters.isEmpty()) {
+      (list as PyElement).delete()
+    }
+  }
+}

python/python-psi-impl/src/com/jetbrains/python/inspections/unusedLocal/PyUnusedLocalInspectionVisitor.java

@@ -362,7 +362,7 @@ public final class PyUnusedLocalInspectionVisitor extends PyInspectionVisitor {
         final PsiElement name = typeParameter.getNameIdentifier();
         registerWarning(name != null ? name : element,
                         PyPsiBundle.message("INSP.unused.locals.type.parameter.isnot.used", typeParameter.getName()),
-                        new PyRemoveStatementQuickFix());
+                        new PyRemoveTypeParameterQuickFix());
       }
       else {
         // Local variable or parameter

python/testData/quickFixes/PyRemoveUnusedLocalQuickFixTest/removeUnusedTypeParameterInFunction.py

@@ -0,0 +1,4 @@
+from typing import Callable
+
+def foo[T, <caret>U](fn: Callable[..., T]) -> T:
+    return fn()

python/testData/quickFixes/PyRemoveUnusedLocalQuickFixTest/removeUnusedTypeParameterInFunction_after.py

@@ -0,0 +1,4 @@
+from typing import Callable
+
+def foo[T](fn: Callable[..., T]) -> T:
+    return fn()

python/testData/quickFixes/PyRemoveUnusedLocalQuickFixTest/removeUnusedTypeParameterInTypeAlias.py

@@ -0,0 +1,3 @@
+from typing import Callable
+
+type Alias[T, <caret>U] = Callable[..., T]

python/testData/quickFixes/PyRemoveUnusedLocalQuickFixTest/removeUnusedTypeParameterInTypeAlias_after.py

@@ -0,0 +1,3 @@
+from typing import Callable
+
+type Alias[T] = Callable[..., T]

python/testSrc/com/jetbrains/python/quickFixes/PyRemoveUnusedLocalQuickFixTest.java

@@ -103,4 +103,16 @@ public class PyRemoveUnusedLocalQuickFixTest extends PyQuickFixTestCase {
   public void testComprehensionIterator() {
     doQuickFixTest(PyUnusedLocalInspection.class, PyPsiBundle.message("INSP.unused.locals.replace.with.wildcard"));
   }
+
+  // PY-85080
+  public void testRemoveUnusedTypeParameterInFunction() {
+    runWithLanguageLevel(LanguageLevel.PYTHON312,
+                         () -> doQuickFixTest(PyUnusedLocalInspection.class, PyPsiBundle.message("QFIX.NAME.remove.type.parameter")));
+  }
+
+  // PY-85080
+  public void testRemoveUnusedTypeParameterInTypeAlias() {
+    runWithLanguageLevel(LanguageLevel.PYTHON312,
+                         () -> doQuickFixTest(PyUnusedLocalInspection.class, PyPsiBundle.message("QFIX.NAME.remove.type.parameter")));
+  }
 }