Fix for EA-68871 #EA-68871 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/when/SwitchCodegenUtil.java

@@ -47,7 +47,7 @@ public class SwitchCodegenUtil {
                 // ensure that expression is constant
                 JetExpression patternExpression = ((JetWhenConditionWithExpression) condition).getExpression();
 
-                assert patternExpression != null : "expression in when should not be null";
+                if (patternExpression == null) return false;
 
                 CompileTimeConstant constant = ExpressionCodegen.getCompileTimeConstant(patternExpression, bindingContext);
                 if (constant == null || !predicate.invoke(constant)) {

compiler/frontend/src/org/jetbrains/kotlin/cfg/WhenChecker.java

@@ -149,9 +149,12 @@ public final class WhenChecker {
         for (JetWhenEntry entry : expression.getEntries()) {
             for (JetWhenCondition condition : entry.getConditions()) {
                 if (condition instanceof JetWhenConditionWithExpression) {
-                    JetType type = trace.getBindingContext().getType(((JetWhenConditionWithExpression) condition).getExpression());
-                    if (type != null && KotlinBuiltIns.isNothingOrNullableNothing(type)) {
-                        return true;
+                    JetWhenConditionWithExpression conditionWithExpression = (JetWhenConditionWithExpression) condition;
+                    if (conditionWithExpression.getExpression() != null) {
+                        JetType type = trace.getBindingContext().getType(conditionWithExpression.getExpression());
+                        if (type != null && KotlinBuiltIns.isNothingOrNullableNothing(type)) {
+                            return true;
+                        }
                     }
                 }
             }

compiler/testData/diagnostics/tests/when/EmptyConditionWithExpression.kt

@@ -0,0 +1,8 @@
+// EA-68871: empty when condition
+fun foo(arg: Int): Int {
+    when (arg) {
+        0 -> return 0
+        <!SYNTAX!><!>-> return 4
+        else -> return -1
+    }
+}

compiler/testData/diagnostics/tests/when/EmptyConditionWithExpression.txt

@@ -0,0 +1,3 @@
+package
+
+internal fun foo(/*0*/ arg: kotlin.Int): kotlin.Int

compiler/testData/diagnostics/tests/when/EmptyConditionWithExpressionEnum.kt

@@ -0,0 +1,9 @@
+// EA-68871: empty when condition
+enum class My { FIRST, SECOND }
+fun foo(arg: My): Int {
+    when (arg) {
+        My.FIRST -> return 0
+        <!SYNTAX!><!>-> return 4
+        else -> return -1
+    }
+}

compiler/testData/diagnostics/tests/when/EmptyConditionWithExpressionEnum.txt

@@ -0,0 +1,37 @@
+package
+
+internal fun foo(/*0*/ arg: My): kotlin.Int
+
+internal final enum class My : kotlin.Enum<My> {
+    public enum entry FIRST : My {
+        private constructor FIRST()
+        public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: My): kotlin.Int
+        public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+        public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public enum entry SECOND : My {
+        private constructor SECOND()
+        public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: My): kotlin.Int
+        public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+        public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    private constructor My()
+    public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: My): kotlin.Int
+    public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+    public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    // Static members
+    public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): My
+    public final /*synthesized*/ fun values(): kotlin.Array<My>
+}

compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java

@@ -13584,6 +13584,18 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("EmptyConditionWithExpression.kt")
+            public void testEmptyConditionWithExpression() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/when/EmptyConditionWithExpression.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("EmptyConditionWithExpressionEnum.kt")
+            public void testEmptyConditionWithExpressionEnum() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/when/EmptyConditionWithExpressionEnum.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("ExhaustiveBoolean.kt")
             public void testExhaustiveBoolean() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/when/ExhaustiveBoolean.kt");