[java] switch expressions: basic highlighting (IDEA-196643)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting12/SwitchExpressions.java

@@ -0,0 +1,48 @@
+import java.util.Random;
+
+class SwitchExpressions {
+  enum E { E1, E2 }
+
+  void m() {
+    System.out.println(switch (new Random().nextInt()) {
+      default -> "whatever";
+    });
+
+    System.out.println(<error descr="'switch' expression does not have any case clauses">switch (new Random().nextInt()) { }</error>);
+
+    System.out.println(switch (new Random().nextInt()) {
+      case 0 -> throw new IllegalStateException("no args");
+      <error descr="Different case kinds used in the switch">case 1:</error> break;
+    });
+
+    System.out.println(
+      switch (<error descr="Incompatible types. Found: 'java.lang.Object', required: 'char, byte, short, int, Character, Byte, Short, Integer, String, or an enum'">new Object()</error>) {
+        default -> "whatever";
+      }
+    );
+
+    System.out.println(switch (E.valueOf("E1")) {
+      case <error descr="Constant expression required">null</error> -> 0;
+      case <error descr="An enum switch case label must be the unqualified name of an enumeration constant">E.E1</error> -> 1;
+      case E2 -> 2;
+      case <error descr="Incompatible types. Found: 'int', required: 'SwitchExpressions.E'">1</error> -> 1;
+    });
+
+    System.out.println(switch (new Random().nextInt()) {
+      <error descr="Duplicate default label">default</error> -> -1;
+      case 1 -> 1;
+      <error descr="Duplicate default label">default</error> -> 0;
+    });
+
+    System.out.println(switch (<error descr="'switch' expression does not cover all possible input values">new Random().nextInt()</error>) {
+      case 1 -> 1;
+    });
+    System.out.println(switch (<error descr="'switch' expression does not cover all possible input values">E.valueOf("E1")</error>) {
+      case E1 -> 1;
+    });
+    System.out.println(switch (E.valueOf("E1")) {
+      case E1 -> 1;
+      case E2 -> 2;
+    });
+  }
+}