[^romka] IDEA-68894 Usages in switch case don't count for unused definition inspection(cherry picked from commit 884425d)

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/controlFlow/impl/ControlFlowBuilder.java

@@ -586,6 +586,11 @@ public class ControlFlowBuilder extends GroovyRecursiveElementVisitor {
 
   @Override
   public void visitCaseSection(GrCaseSection caseSection) {
+    GrExpression value = caseSection.getCaseLabel().getValue();
+    if (value != null) {
+      value.accept(this);
+    }
+
     for (GrStatement statement : caseSection.getStatements()) {
       statement.accept(this);
     }

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/GroovyHighlightingTest.groovy

@@ -187,6 +187,7 @@ public class GroovyHighlightingTest extends LightCodeInsightFixtureTestCase {
   public void testUnusedVariable() throws Exception { doTest(new UnusedDefInspection()); }
   public void testDefinitionUsedInClosure() throws Exception { doTest(new UnusedDefInspection()); }
   public void testDefinitionUsedInClosure2() throws Exception { doTest(new UnusedDefInspection()); }
+  public void testDefinitionUsedInSwitchCase() throws Exception { doTest(new UnusedDefInspection()); }
   public void testDuplicateInnerClass() throws Throwable{doTest();}
 
   public void testThisInStaticContext() throws Throwable {doTest();}

plugins/groovy/testdata/highlighting/DefinitionUsedInSwitchCase.groovy

@@ -0,0 +1,9 @@
+def m = [a: 1, b: 2]
+def <warning descr="Assignment is not used">m1</warning> = [a: 1, b: 2]
+def val = 'a'
+
+switch (val) {
+  case m: "key in map"; break
+// equivalent to case { val in m }: ...
+  default: "not in map"
+}