Fix various issues with static methods, fixes #416

Reviewed-on: #431

resources/bytecode/javFiles/Bug411.jav

@@ -0,0 +1,7 @@
+import java.lang.Integer;
+
+public interface Bug411 {
+    default f() {
+        return 1;
+    }
+}

resources/bytecode/javFiles/Bug412.jav

@@ -0,0 +1,12 @@
+import java.lang.Integer;
+
+public class Bug412 {
+    public m(Integer i) {
+        var r = 0;
+        switch (i) {
+            case 1: r = 10; break;
+            default: r = 20;
+        }
+        return r;
+    }
+}

resources/bytecode/javFiles/Bug416.jav

@@ -0,0 +1,9 @@
+import java.lang.Integer;
+sealed interface L<T> permits Cons, Nil {}
+public record Cons<T>(T head, L<T> tail) implements L<T> {}
+public record Nil<T>() implements L<T> {}
+
+public class Bug416 {
+    public static <T> len(Cons(h, t)) { return 1 + len(t); }
+    public static <T> len(Nil()) { return 0; }
+}

src/main/java/de/dhbwstuttgart/bytecode/Codegen.java

@@ -1780,7 +1780,7 @@ public class Codegen {
             if (parent != null) {
                 state.scope.parent = parent.scope;
             }
-            var offset = 1;
+            var offset = method.isStatic() ? 0 : 1;
             for (var param : method.signature().parameters()) {
                 state.createVariable(param.pattern().name(), param.pattern().type());
             }

src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/FCGenerator.java

@@ -15,6 +15,7 @@ import de.dhbwstuttgart.typeinference.constraints.Pair;
 import de.dhbwstuttgart.typeinference.unify.PlaceholderRegistry;
 import de.dhbwstuttgart.typeinference.unify.model.*;
 
+import java.lang.reflect.Modifier;
 import java.util.*;
 import java.util.stream.Collectors;
 
@@ -54,7 +55,8 @@ public class FCGenerator {
     
     
     private static Boolean isFunctionalInterface(ClassOrInterface cly)	{
-    	return (cly.isInterface() && (cly.isFunctionalInterface() || cly.getMethods().size() == 1)); 
+        // TODO isFunctionalInterface should be set properly, we shouldn't need to check it again
+        return (cly.isInterface() && (cly.isFunctionalInterface() || cly.getMethods().size() == 1 && Modifier.isAbstract(cly.getMethods().getFirst().modifier)));
     }
     
     private static Pair genImplFunType(ClassOrInterface cly, RefTypeOrTPHOrWildcardOrGeneric fIType, HashMap<String, RefTypeOrTPHOrWildcardOrGeneric> gtvs) {

src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/StatementGenerator.java

@@ -405,14 +405,16 @@ public class StatementGenerator {
 
     private SwitchBlock convert(Java17Parser.SwitchBlockStatementGroupContext stmt) {
         List<SwitchLabel> labels = new ArrayList<>();
-        stmt.switchLabel().forEach((label) -> {
+        var isDefault = false;
+        for (var label : stmt.switchLabel()) {
+            if (label instanceof SwitchLabelDefaultContext) isDefault = true;
             labels.add(convert(label));
-        });
+        }
         List<Statement> block = new ArrayList<>();
         stmt.blockStatement().stream().forEach((blockStmt) -> {
             block.addAll(convert(blockStmt));
         });
-        return new SwitchBlock(labels, new Block(block, stmt.blockStatement(0).getStart()), false, stmt.getStart());
+        return new SwitchBlock(labels, new Block(block, stmt.blockStatement(0).getStart()), isDefault,false, stmt.getStart());
     }
 
     private SwitchLabel convert(SwitchLabelContext switchLabel) {

src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/SyntaxTreeGenerator.java

@@ -409,8 +409,9 @@ public class SyntaxTreeGenerator {
       }
     }
 
+    boolean isFunctonalInterfce = methods.size() == 1 && Modifier.isAbstract(methods.getFirst().modifier);
     var staticCtor = Optional.of(this.generateStaticConstructor(ctx.identifier().getText(), staticFieldInitializations, genericParams, ctx.getStart()));
-    return new ClassOrInterface(modifiers, name, fields, Optional.empty(), staticCtor, methods, new ArrayList<>(), genericParams, superClass, true, methods.size() == 1 ? true : false, extendedInterfaces, permittedSubtypes, ctx.getStart(), fileName);
+    return new ClassOrInterface(modifiers, name, fields, Optional.empty(), staticCtor, methods, new ArrayList<>(), genericParams, superClass, true, isFunctonalInterfce, extendedInterfaces, permittedSubtypes, ctx.getStart(), fileName);
   }
 
   private GenericDeclarationList createEmptyGenericDeclarationList(Token classNameIdentifier) {

src/main/java/de/dhbwstuttgart/target/generate/ASTToTargetAST.java

@@ -29,6 +29,7 @@ import org.objectweb.asm.Opcodes;
 
 import java.lang.classfile.Opcode;
 import java.lang.reflect.AccessFlag;
+import java.lang.reflect.Modifier;
 import java.util.*;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -630,7 +631,7 @@ public class ASTToTargetAST {
                 mParams,
                 classType,
                 method.name(),
-                false, false, method.isPrivate()
+                method.isStatic(), false, method.isPrivate()
         );
         if (method.signature().returnType() != null) {
             caseBody = new TargetReturn(caseBody);

src/main/java/de/dhbwstuttgart/target/generate/StatementToTargetExpression.java

@@ -476,7 +476,7 @@ public class StatementToTargetExpression implements ASTVisitor {
                     .map(this::extractAllPatterns)
                     .flatMap(List::stream).toList();
             case FormalParameter param -> List.of(new TypeVariants(param.getType(), converter.findAllVariants(param.getType())));
-            default -> List.of();
+            case null, default -> List.of();
         };
     }
 

src/test/java/TestComplete.java

@@ -1759,4 +1759,37 @@ public class TestComplete {
         assertEquals("one", name.invoke(instance, 1));
         assertEquals("many", name.invoke(instance, 2));
     }
+
+    @Test
+    public void testBug411() throws Exception {
+        var classFiles = generateClassFiles(createClassLoader(), "Bug411.jav");
+        var clazz = classFiles.get("Bug411");
+    }
+
+    @Test
+    public void testBug412() throws Exception {
+        var classFiles = generateClassFiles(createClassLoader(), "Bug412.jav");
+        var clazz = classFiles.get("Bug412");
+        var instance = clazz.getDeclaredConstructor().newInstance();
+        var m = clazz.getDeclaredMethod("m", Integer.class);
+        assertEquals(10, m.invoke(instance, 1));
+        assertEquals(20, m.invoke(instance, 2));
+    }
+
+    @Test
+    public void testBug416() throws Exception {
+        var classFiles = generateClassFiles(createClassLoader(), "Bug416.jav");
+        var clazz = classFiles.get("Bug416");
+        var L = classFiles.get("L");
+        var Cons = classFiles.get("Cons");
+        var Nil = classFiles.get("Nil");
+
+        var consCtor = Cons.getDeclaredConstructor(Object.class, L);
+        var nilCtor = Nil.getDeclaredConstructor();
+
+        var list = consCtor.newInstance(1, consCtor.newInstance(2, consCtor.newInstance(3, nilCtor.newInstance())));
+
+        var len = clazz.getDeclaredMethod("len", L);
+        assertEquals(3, len.invoke(null, list));
+    }
 }