Add overloading for switches, see #348

resources/bytecode/javFiles/SwitchOverload.jav

@@ -0,0 +1,17 @@
+import java.lang.Integer;
+import java.lang.Double;
+import java.lang.Number;
+
+public record R(Number n) {}
+
+public class SwitchOverload {
+
+    Number f(Double d) { return d * 2; }
+    Number f(Integer i) { return i * 5; }
+
+    public m(r) {
+        return switch(r) {
+            case R(o) -> f(o);
+        };
+    }
+}

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

@@ -1294,7 +1294,6 @@ public class Codegen {
         state.enterScope();
         // This is the index to start the switch from
         mv.visitInsn(ICONST_0);
-        if (aSwitch.isExpression())
         state.pushSwitch();
 
         // To be able to skip ahead to the next case

src/main/java/de/dhbwstuttgart/syntaxtree/type/RefType.java

@@ -8,6 +8,7 @@ import org.antlr.v4.runtime.Token;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Objects;
 
 
 public class RefType extends RefTypeOrTPHOrWildcardOrGeneric
@@ -49,10 +50,7 @@ public class RefType extends RefTypeOrTPHOrWildcardOrGeneric
 
     @Override
 	public int hashCode() {
-    	int hash = 0;
-    	hash += super.hashCode();
-    	hash += this.name.hashCode();//Nur den Name hashen. Sorgt für langsame, aber funktionierende HashMaps
-        return hash;
+        return this.name.hashCode();//Nur den Name hashen. Sorgt für langsame, aber funktionierende HashMaps
 	}
 
     public RefType(JavaClassName fullyQualifiedName, List<RefTypeOrTPHOrWildcardOrGeneric> parameter, Token offset) {
@@ -83,6 +81,7 @@ public class RefType extends RefTypeOrTPHOrWildcardOrGeneric
     public boolean equals(Object obj)
     {
         if(obj instanceof RefType){
+            if (!Objects.equals(this.name, ((RefType) obj).name)) return false;
             boolean ret = true;
             
             //if(!(super.equals(obj))) PL 2020-03-12 muss vll. einkommentiert werden   

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

@@ -39,6 +39,10 @@ public class ASTToTargetAST {
 
     public final JavaTXCompiler compiler;
 
+    public List<RefTypeOrTPHOrWildcardOrGeneric> findAllVariants(RefTypeOrTPHOrWildcardOrGeneric type) {
+        return javaGenerics().stream().map(generics -> generics.resolve(type)).distinct().toList();
+    }
+
     public List<GenericsResult> txGenerics() {
         return all.stream().map(generics -> new GenericsResult(generics.txGenerics)).toList();
     }

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

@@ -134,8 +134,8 @@ public abstract class GenerateGenerics {
     final Map<Method, Set<Pair>> familyOfMethods = new HashMap<>();
 
     final Set<PairLT> simplifiedConstraints = new HashSet<>();
-    final Map<TPH, RefTypeOrTPHOrWildcardOrGeneric> concreteTypes = new HashMap<>();
-    final Map<TypePlaceholder, TypePlaceholder> equality = new HashMap<>();
+    Map<TPH, RefTypeOrTPHOrWildcardOrGeneric> concreteTypes = new HashMap<>();
+    Map<TypePlaceholder, TypePlaceholder> equality = new HashMap<>();
 
     GenerateGenerics(ASTToTargetAST astToTargetAST, ResultSet constraints) {
         this.astToTargetAST = astToTargetAST;
@@ -154,6 +154,22 @@ public abstract class GenerateGenerics {
         System.out.println("Simplified constraints: " + simplifiedConstraints);
     }
 
+    /*public record GenericsState(Map<TPH, RefTypeOrTPHOrWildcardOrGeneric> concreteTypes, Map<TypePlaceholder, TypePlaceholder> equality) {}
+
+    public GenericsState store() {
+        return new GenericsState(new HashMap<>(concreteTypes), new HashMap<>(equality));
+    }
+
+    public void restore(GenericsState state) {
+        this.concreteTypes = state.concreteTypes;
+        this.equality = state.equality;
+    }
+
+    public void addOverlay(TypePlaceholder from, RefTypeOrTPHOrWildcardOrGeneric to) {
+        if (to instanceof TypePlaceholder t) equality.put(from, t);
+        else if (to instanceof RefType t) concreteTypes.put(new TPH(from), t);
+    }*/
+
     Set<TPH> findTypeVariables(RefTypeOrTPHOrWildcardOrGeneric type) {
         var result = new HashSet<TPH>();
         if (type instanceof TypePlaceholder tph) {

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

@@ -2,23 +2,19 @@ package de.dhbwstuttgart.target.generate;
 
 import de.dhbwstuttgart.exceptions.DebugException;
 import de.dhbwstuttgart.exceptions.NotImplementedException;
-import de.dhbwstuttgart.parser.NullToken;
 import de.dhbwstuttgart.parser.SyntaxTreeGenerator.AssignToLocal;
 import de.dhbwstuttgart.parser.scope.JavaClassName;
 import de.dhbwstuttgart.syntaxtree.*;
-import de.dhbwstuttgart.syntaxtree.factory.PrimitiveMethodsGenerator;
 import de.dhbwstuttgart.syntaxtree.statement.*;
 import de.dhbwstuttgart.syntaxtree.type.*;
 import de.dhbwstuttgart.target.tree.MethodParameter;
-import de.dhbwstuttgart.target.tree.TargetGeneric;
 import de.dhbwstuttgart.target.tree.TargetMethod;
 import de.dhbwstuttgart.target.tree.expression.*;
 import de.dhbwstuttgart.target.tree.type.*;
 
-import javax.swing.text.html.Option;
 import java.lang.reflect.Modifier;
 import java.util.*;
-import java.util.stream.Stream;
+import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
 public class StatementToTargetExpression implements ASTVisitor {
@@ -386,9 +382,94 @@ public class StatementToTargetExpression implements ASTVisitor {
         result = new TargetTernary(converter.convert(ternary.getType()), converter.convert(ternary.cond), converter.convert(ternary.iftrue), converter.convert(ternary.iffalse));
     }
 
+    record TypeVariants(RefTypeOrTPHOrWildcardOrGeneric in, List<RefTypeOrTPHOrWildcardOrGeneric> types) {}
+
+    private List<TypeVariants> extractAllPatterns(Pattern pattern) {
+        return switch (pattern) {
+            case GuardedPattern guarded -> extractAllPatterns(guarded.getNestedPattern());
+            case RecordPattern recordPattern -> recordPattern.getSubPattern().stream()
+                    .map(this::extractAllPatterns)
+                    .flatMap(List::stream).toList();
+            case FormalParameter param -> List.of(new TypeVariants(param.getType(), converter.findAllVariants(param.getType())));
+            default -> List.of();
+        };
+    }
+
+    record TypePair(RefTypeOrTPHOrWildcardOrGeneric in, RefTypeOrTPHOrWildcardOrGeneric out) {}
+
+    private void cartesianProduct(
+            List<TypeVariants> variants, int index,
+            List<RefTypeOrTPHOrWildcardOrGeneric> current,
+            List<List<RefTypeOrTPHOrWildcardOrGeneric>> result) {
+
+        if (index == variants.size()) {
+            result.add(new ArrayList<>(current));
+            return;
+        }
+        var currentSet = variants.get(index).types;
+        for (var element: currentSet) {
+            current.add(element);
+            cartesianProduct(variants, index + 1, current, result);
+            current.removeLast();
+        }
+    }
+
+    private List<List<TypePair>> cartesianProduct(List<TypeVariants> variants) {
+        var prod = new ArrayList<List<RefTypeOrTPHOrWildcardOrGeneric>>();
+        cartesianProduct(variants, 0, new ArrayList<>(), prod);
+
+        var res = new ArrayList<List<TypePair>>();
+        for (var list : prod) {
+            var l = new ArrayList<TypePair>();
+            for (var i = 0; i < list.size(); i++) {
+                l.add(new TypePair(variants.get(i).in, list.get(i)));
+            }
+            res.add(l);
+        }
+        return res;
+    }
+
     @Override
     public void visit(Switch switchStmt) {
-        var cases = switchStmt.getBlocks().stream().filter(s -> !s.isDefault()).map(converter::convert).toList();
+        var variants = converter.findAllVariants(switchStmt.getSwitch().getType());
+        var returns = converter.findAllVariants(switchStmt.getType());
+        var canBeOverloaded = variants.size() == 1 && returns.size() == 1;
+
+        var cases = switchStmt.getBlocks().stream().filter(s -> !s.isDefault()).map(case_ -> {
+            var overloads = new ArrayList<TargetSwitch.Case>();
+
+            if (canBeOverloaded) {
+                for (var label: case_.getLabels()) {
+                    var product = cartesianProduct(extractAllPatterns(label.getPattern()));
+
+                    for (var l : product) {
+                        var oldGenerics = converter.generics;
+
+                        // Set the generics to matching result set
+                        for (var generics : converter.all) {
+                            var java = generics.javaGenerics();
+                            var equals = true;
+                            for (var pair : l) {
+                                if (!java.getType(pair.in).equals(pair.out)) {
+                                    equals = false; break;
+                                }
+                            }
+                            if (equals) {
+                                converter.generics = generics;
+                                break;
+                            }
+                        }
+
+                        overloads.add(converter.convert(case_));
+                        converter.generics = oldGenerics;
+                    }
+                }
+            } else {
+                overloads.add(converter.convert(case_));
+            }
+
+            return overloads;
+        }).flatMap(List::stream).toList();
 
         TargetSwitch.Case default_ = null;
         for (var block : switchStmt.getBlocks()) {

src/main/java/de/dhbwstuttgart/target/tree/TargetMethod.java

@@ -18,6 +18,19 @@ public record TargetMethod(int access, String name, TargetBlock block, Signature
         public String getDescriptor() {
             return TargetMethod.getDescriptor(returnType, parameters.stream().map(MethodParameter::pattern).map(TargetPattern::type).toArray(TargetType[]::new));
         }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Signature signature = (Signature) o;
+            return Objects.equals(parameters, signature.parameters);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(parameters);
+        }
     }
 
     public static String getDescriptor(TargetType returnType, TargetType... parameters) {

src/test/java/TestComplete.java

@@ -849,6 +849,24 @@ public class TestComplete {
         assertEquals(m2.invoke(instance, 10), 10);
     }
 
+    @Test
+    public void testOverloadSwitch() throws Exception {
+        var classFiles = generateClassFiles(new ByteArrayClassLoader(), "SwitchOverload.jav");
+        var clazz = classFiles.get("SwitchOverload");
+
+        var R = classFiles.get("R");
+        var rctor = R.getDeclaredConstructor(Number.class);
+
+        var instance = clazz.getDeclaredConstructor().newInstance();
+        var m = clazz.getDeclaredMethod("m", R);
+
+        var x = rctor.newInstance(10);
+        var d = rctor.newInstance(20.0);
+
+        assertEquals(m.invoke(instance, x), 50);
+        assertEquals(m.invoke(instance, d), 40.0);
+    }
+
     @Test
     public void testInterfaces() throws Exception {
         var classFiles = generateClassFiles(new ByteArrayClassLoader(), "Interfaces.jav");