Perform additional checks on catch parameter declaration

KT-8320 It should not be possible to catch a type parameter type
KT-7645 Prohibit default value for `catch`-block parameter

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -152,6 +152,7 @@ public interface Errors {
     DiagnosticFactory0<KtTypeArgumentList> TYPE_ARGUMENTS_FOR_OUTER_CLASS_WHEN_NESTED_REFERENCED = DiagnosticFactory0.create(ERROR);
 
     DiagnosticFactory0<KtParameter> REIFIED_TYPE_IN_CATCH_CLAUSE = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<KtParameter> TYPE_PARAMETER_IN_CATCH_CLAUSE = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeParameterList> GENERIC_THROWABLE_SUBCLASS = DiagnosticFactory0.create(ERROR);
 
     DiagnosticFactory0<KtTypeAlias> TOPLEVEL_TYPEALIASES_ONLY = DiagnosticFactory0.create(ERROR);
@@ -527,6 +528,8 @@ public interface Errors {
     DiagnosticFactory0<KtParameter> DATA_CLASS_VARARG_PARAMETER = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtParameter> DATA_CLASS_NOT_PROPERTY_PARAMETER = DiagnosticFactory0.create(ERROR);
 
+    DiagnosticFactory0<KtParameter> CATCH_PARAMETER_WITH_DEFAULT_VALUE = DiagnosticFactory0.create(ERROR);
+
     // Multi-platform projects
 
     DiagnosticFactory0<KtDeclaration> HEADER_DECLARATION_WITH_BODY = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -621,6 +621,7 @@ public class DefaultErrorMessages {
         MAP.put(TYPE_ARGUMENTS_FOR_OUTER_CLASS_WHEN_NESTED_REFERENCED, "Type arguments for outer class are redundant when nested class is referenced");
 
         MAP.put(REIFIED_TYPE_IN_CATCH_CLAUSE, "Reified type is forbidden for catch parameter");
+        MAP.put(TYPE_PARAMETER_IN_CATCH_CLAUSE, "Type parameter is forbidden for catch parameter");
         MAP.put(GENERIC_THROWABLE_SUBCLASS, "Subclass of 'Throwable' may not have type parameters");
 
         MAP.put(TYPE_MISMATCH_IN_FOR_LOOP, "The loop iterates over values of type {0} but the parameter is declared to be {1}", RENDER_TYPE,
@@ -797,6 +798,8 @@ public class DefaultErrorMessages {
         MAP.put(DATA_CLASS_VARARG_PARAMETER, "Primary constructor vararg parameters are forbidden for data classes");
         MAP.put(DATA_CLASS_NOT_PROPERTY_PARAMETER, "Data class primary constructor must have only property (val / var) parameters");
 
+        MAP.put(CATCH_PARAMETER_WITH_DEFAULT_VALUE, "Catch clause parameter may not have a default value");
+
         MAP.put(AMBIGUOUS_ANONYMOUS_TYPE_INFERRED, "Right-hand side has anonymous type. Please specify type explicitly", TO_STRING);
         MAP.put(KCLASS_WITH_NULLABLE_TYPE_PARAMETER_IN_SIGNATURE,
                 "Declaration has an inconsistent return type. Please add upper bound Any for type parameter ''{0}'' or specify return type explicitly", NAME);

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/ControlStructureTypingVisitor.java

@@ -23,6 +23,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
 import org.jetbrains.kotlin.descriptors.*;
+import org.jetbrains.kotlin.diagnostics.Errors;
 import org.jetbrains.kotlin.psi.*;
 import org.jetbrains.kotlin.resolve.BindingContext;
 import org.jetbrains.kotlin.resolve.BindingContextUtils;
@@ -486,17 +487,12 @@ public class ControlStructureTypingVisitor extends ExpressionTypingVisitor {
             KtExpression catchBody = catchClause.getCatchBody();
             boolean nothingInCatchBranch = false;
             if (catchParameter != null) {
-                components.identifierChecker.checkDeclaration(catchParameter, context.trace);
+                checkCatchParameterDeclaration(catchParameter, context);
-                ModifiersChecker.ModifiersCheckingProcedure modifiersChecking = components.modifiersChecker.withTrace(context.trace);
-                modifiersChecking.checkParameterHasNoValOrVar(catchParameter, VAL_OR_VAR_ON_CATCH_PARAMETER);
-                ModifierCheckerCore.INSTANCE.check(catchParameter, context.trace, null, components.languageVersionSettings);
 
                 VariableDescriptor variableDescriptor = components.descriptorResolver.resolveLocalVariableDescriptor(
                         context.scope, catchParameter, context.trace);
                 KotlinType catchParameterType = variableDescriptor.getType();
-                if (TypeUtils.isReifiedTypeParameter(catchParameterType)) {
+                checkCatchParameterType(catchParameter, catchParameterType, context);
-                    context.trace.report(REIFIED_TYPE_IN_CATCH_CLAUSE.on(catchParameter));
-                }
 
                 KotlinType throwableType = components.builtIns.getThrowable().getDefaultType();
                 components.dataFlowAnalyzer.checkType(catchParameterType, catchParameter, context.replaceExpectedType(throwableType));
@@ -539,6 +535,29 @@ public class ControlStructureTypingVisitor extends ExpressionTypingVisitor {
         }
     }
 
+    private static void checkCatchParameterType(KtParameter catchParameter, KotlinType catchParameterType, ExpressionTypingContext context) {
+        TypeParameterDescriptor typeParameterDescriptor = TypeUtils.getTypeParameterDescriptorOrNull(catchParameterType);
+        if (typeParameterDescriptor != null) {
+            if (typeParameterDescriptor.isReified()) {
+                context.trace.report(REIFIED_TYPE_IN_CATCH_CLAUSE.on(catchParameter));
+            }
+            else {
+                context.trace.report(TYPE_PARAMETER_IN_CATCH_CLAUSE.on(catchParameter));
+            }
+        }
+    }
+
+    private void checkCatchParameterDeclaration(KtParameter catchParameter, ExpressionTypingContext context) {
+        components.identifierChecker.checkDeclaration(catchParameter, context.trace);
+        ModifiersChecker.ModifiersCheckingProcedure modifiersChecking = components.modifiersChecker.withTrace(context.trace);
+        modifiersChecking.checkParameterHasNoValOrVar(catchParameter, VAL_OR_VAR_ON_CATCH_PARAMETER);
+        ModifierCheckerCore.INSTANCE.check(catchParameter, context.trace, null, components.languageVersionSettings);
+
+        if (catchParameter.hasDefaultValue()) {
+            context.trace.report(Errors.CATCH_PARAMETER_WITH_DEFAULT_VALUE.on(catchParameter));
+        }
+    }
+
     @Override
     public KotlinTypeInfo visitThrowExpression(@NotNull KtThrowExpression expression, ExpressionTypingContext context) {
         KtExpression thrownExpression = expression.getThrownExpression();

compiler/testData/diagnostics/tests/controlStructures/catchGenerics.kt

@@ -19,3 +19,7 @@ inline fun <reified E : Exception, R> tryCatch(lazy: () -> R, failure: (E) -> R)
     } catch (<!REIFIED_TYPE_IN_CATCH_CLAUSE!>e: E<!>) {
         failure(e)
     }
+
+fun <T : Throwable> tryCatch() {
+    try { } catch (<!TYPE_PARAMETER_IN_CATCH_CLAUSE!>e: T<!>) { }
+}

compiler/testData/diagnostics/tests/controlStructures/catchGenerics.txt

@@ -1,6 +1,7 @@
 package
 
 public fun bar(): kotlin.Unit
+public fun </*0*/ T : kotlin.Throwable> tryCatch(): kotlin.Unit
 public inline fun </*0*/ reified E : kotlin.Exception /* = java.lang.Exception */, /*1*/ R> tryCatch(/*0*/ lazy: () -> R, /*1*/ failure: (E) -> R): R
 
 public final class XException</*0*/ T> : kotlin.Throwable {

compiler/testData/diagnostics/tests/controlStructures/catchWithDefault.kt

@@ -0,0 +1,3 @@
+fun test() {
+    try { } catch (<!CATCH_PARAMETER_WITH_DEFAULT_VALUE!>e: Exception = <!DEBUG_INFO_MISSING_UNRESOLVED!>Exception<!>()<!>) { }
+}

compiler/testData/diagnostics/tests/controlStructures/catchWithDefault.txt

@@ -0,0 +1,3 @@
+package
+
+public fun test(): kotlin.Unit

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

@@ -4390,6 +4390,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("catchWithDefault.kt")
+            public void testCatchWithDefault() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/controlStructures/catchWithDefault.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("commonSupertypeOfT.kt")
             public void testCommonSupertypeOfT() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/controlStructures/commonSupertypeOfT.kt");

js/js.translator/testData/box/regression/kt2470.kt

@@ -2,12 +2,12 @@
 
 package foo
 
-public fun <T : Throwable> failsWith(block: () -> Any): T {
+public inline fun <reified T : Throwable> failsWith(block: () -> Any): T {
     try {
         block()
     }
-    catch (e: T) {
+    catch (e: Throwable) {
-        return e
+        if (e is T) return e
     }
 
     throw Exception("Should have failed")