Allow nested generic specialization keys (#1266)

* Allow nested generic specialization keys

* Normalize nested specialization bindings

* Isolate Lua generic static storage

* Track erased generic static ownership

* Materialize statics for erased instantiations

* Preserve generic static initializer order

* Specialize static-owning generic factories

* Handle inherited generic static storage

* Register erased generic helper statics

* Collect fixed generic method operations

* Preserve implicit generic reachability

Author: Frotty

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstio/WurstCompilerJassImpl.java

@@ -875,10 +875,11 @@ public LuaCompilationUnit transformProgToLua() {
         ImAttrType.setWurstClassType(null);
         int stage;
         boolean specializeTupleValueTypes = containsTupleTypeArgument();
-        if (containsGenericNewCall() || containsTypeClassDispatch() || specializeTupleValueTypes) {
+        EliminateGenerics luaGenerics = new EliminateGenerics(getImTranslator(), getImProg());
+        if (containsGenericNewCall() || containsTypeClassDispatch() || specializeTupleValueTypes
+            || luaGenerics.hasGenericStatics()) {
             beginPhase(2, "Specialize generics for Lua-only concrete operations");
-            new EliminateGenerics(getImTranslator(), getImProg())
-                .transformGenericNewOnly(specializeTupleValueTypes);
+            luaGenerics.transformGenericNewOnly(specializeTupleValueTypes);
             // Remove phantom erased initialization before optimization can preserve only its side
             // effect. A specialized static owns its copied initializer unless the erased static is live.
             RemoveGarbage.removePhantomGenericStaticInitializers(getImProg(), getImTranslator());

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/EliminateGenerics.java

@@ -1,6 +1,5 @@
 package de.peeeq.wurstscript.translation.imtranslation;
 
-import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import de.peeeq.wurstscript.jassIm.*;
 
@@ -16,9 +15,6 @@ class GenericTypes {
 
 
     public GenericTypes(List<ImTypeArgument> typeArguments) {
-        for (ImTypeArgument ta : typeArguments) {
-            Preconditions.checkArgument(!EliminateGenerics.isGenericType(ta.getType()), "Type arguments must not be generic: " + typeArguments);
-        }
         this.typeArguments = ImmutableList.copyOf(typeArguments);
     }
 
@@ -36,7 +32,7 @@ public boolean equals(Object o) {
             for (int i = 0; i < typeArguments.size(); i++) {
                 ImTypeArgument t1 = typeArguments.get(i);
                 ImTypeArgument t2 = ot.typeArguments.get(i);
-                if (!t1.getType().equalsType(t2.getType())) {
+                if (!equalTypeIgnoringBindings(t1.getType(), t2.getType())) {
                     return false;
                 }
                 // Deliberately not comparing the type class binding. It is only a fast path for
@@ -50,6 +46,60 @@ public boolean equals(Object o) {
         return false;
     }
 
+    /**
+     * Type-class bindings are dispatch metadata, not part of a specialization's structural type.
+     * Unlike the general IM type equality operation, this comparison therefore ignores bindings
+     * on every nested class-type argument, not just on the arguments wrapped by this key.
+     */
+    private static boolean equalTypeIgnoringBindings(ImType left, ImType right) {
+        if (left instanceof ImArrayType) {
+            return right instanceof ImArrayType
+                && equalTypeIgnoringBindings(((ImArrayType) left).getEntryType(),
+                ((ImArrayType) right).getEntryType());
+        }
+        if (left instanceof ImArrayTypeMulti) {
+            return right instanceof ImArrayTypeMulti
+                && equalTypeIgnoringBindings(((ImArrayTypeMulti) left).getEntryType(),
+                ((ImArrayTypeMulti) right).getEntryType());
+        }
+        if (left instanceof ImTupleType) {
+            if (!(right instanceof ImTupleType)) {
+                return false;
+            }
+            ImTupleType leftTuple = (ImTupleType) left;
+            ImTupleType rightTuple = (ImTupleType) right;
+            if (leftTuple.getTypes().size() != rightTuple.getTypes().size()) {
+                return false;
+            }
+            for (int i = 0; i < leftTuple.getTypes().size(); i++) {
+                if (!equalTypeIgnoringBindings(leftTuple.getTypes().get(i),
+                    rightTuple.getTypes().get(i))) {
+                    return false;
+                }
+            }
+            return true;
+        }
+        if (left instanceof ImClassType) {
+            if (!(right instanceof ImClassType)) {
+                return false;
+            }
+            ImClassType leftClass = (ImClassType) left;
+            ImClassType rightClass = (ImClassType) right;
+            if (leftClass.getClassDef() != rightClass.getClassDef()
+                || leftClass.getTypeArguments().size() != rightClass.getTypeArguments().size()) {
+                return false;
+            }
+            for (int i = 0; i < leftClass.getTypeArguments().size(); i++) {
+                if (!equalTypeIgnoringBindings(leftClass.getTypeArguments().get(i).getType(),
+                    rightClass.getTypeArguments().get(i).getType())) {
+                    return false;
+                }
+            }
+            return true;
+        }
+        return left.equalsType(right);
+    }
+
     @Override
     public int hashCode() {
         int res = 7;

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/GenericTypes.java

@@ -61,6 +61,7 @@ public record Specialisation(Element original, List<ImTypeArgument> typeArgument
     }
 
     private final Map<Element, Specialisation> specialisations = new IdentityHashMap<>();
+    private final Map<ImClass, Set<GenericTypes>> erasedGenericAllocations = new IdentityHashMap<>();
 
     /**
      * @param typeArguments the arguments the copy was made for, empty when a copy carries none of its
@@ -99,6 +100,31 @@ public void recordGenericStaticOwner(ImVar global, ImClass owner) {
         return specialisations.get(copy);
     }
 
+    public void recordErasedGenericAllocation(ImClass clazz, List<ImTypeArgument> typeArguments) {
+        erasedGenericAllocations.computeIfAbsent(canonical(clazz), ignored -> new HashSet<>())
+            .add(new GenericTypes(typeArguments));
+    }
+
+    public boolean hasErasedAllocationWithoutStaticSpecialization(ImClass clazz, ImVar originalStatic) {
+        Set<GenericTypes> allocations = erasedGenericAllocations.get(canonical(clazz));
+        if (allocations == null || allocations.isEmpty()) {
+            return false;
+        }
+        Set<GenericTypes> specializedStatics = new HashSet<>();
+        for (Map.Entry<Element, Specialisation> entry : specialisations.entrySet()) {
+            Specialisation specialization = entry.getValue();
+            if (specialization.original() == originalStatic) {
+                specializedStatics.add(new GenericTypes(specialization.typeArguments()));
+            }
+        }
+        for (GenericTypes allocation : allocations) {
+            if (!specializedStatics.contains(allocation)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * The node {@code copy} was ultimately copied from, or {@code copy} itself.
      * <p>

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/ImTranslator.java

@@ -190,7 +190,9 @@ public static void removePhantomGenericStaticInitializers(ImProg prog, ImTransla
             changed = false;
             for (ImVar original : candidates.keySet()) {
                 ImClass owner = translator.genericStaticOwnerOf(original);
-                if ((used.getVars().contains(original) || used.getInstantiatedClasses().contains(owner))
+                boolean erasedInstantiationNeedsOriginal = used.getInstantiatedClasses().contains(owner)
+                    && translator.hasErasedAllocationWithoutStaticSpecialization(owner, original);
+                if ((used.getVars().contains(original) || erasedInstantiationNeedsOriginal)
                     && liveOriginals.add(original)) {
                     changed = true;
                 }

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/lua/translation/RemoveGarbage.java

@@ -0,0 +1,64 @@
+package de.peeeq.wurstscript.translation.imtranslation;
+
+import de.peeeq.wurstscript.ast.Ast;
+import de.peeeq.wurstscript.jassIm.ImClass;
+import de.peeeq.wurstscript.jassIm.ImClassType;
+import de.peeeq.wurstscript.jassIm.ImFunction;
+import de.peeeq.wurstscript.jassIm.ImMethod;
+import de.peeeq.wurstscript.jassIm.ImSimpleType;
+import de.peeeq.wurstscript.jassIm.ImTypeArgument;
+import de.peeeq.wurstscript.jassIm.ImTypeClassFunc;
+import de.peeeq.wurstscript.jassIm.JassIm;
+import io.vavr.control.Either;
+import org.testng.annotations.Test;
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.testng.Assert.assertEquals;
+
+public class GenericTypesTests {
+
+    @Test
+    public void nestedTypeClassBindingsDoNotSplitSpecializationKeys() {
+        ImClass box = genericClass("Box");
+        ImClass list = genericClass("List");
+        ImSimpleType integer = JassIm.ImSimpleType("integer");
+        ImTypeClassFunc requirement = JassIm.ImTypeClassFunc(Ast.NoExpr(), "toIndex",
+            JassIm.ImTypeVars(), JassIm.ImVars(), integer);
+        ImFunction instance = JassIm.ImFunction(Ast.NoExpr(), "intToIndex", JassIm.ImTypeVars(),
+            JassIm.ImVars(), integer, JassIm.ImVars(), JassIm.ImStmts(), List.of());
+
+        Map<ImTypeClassFunc, Either<ImMethod, ImFunction>> binding = new LinkedHashMap<>();
+        binding.put(requirement, Either.right(instance));
+        ImClassType unboundBox = JassIm.ImClassType(box,
+            JassIm.ImTypeArguments(argument(integer, Collections.emptyMap())));
+        ImClassType boundBox = JassIm.ImClassType(box,
+            JassIm.ImTypeArguments(argument(integer, binding)));
+
+        GenericTypes unbound = key(list, unboundBox);
+        GenericTypes bound = key(list, boundBox);
+
+        assertEquals(bound, unbound,
+            "type-class dispatch metadata must not change a structural specialization key");
+        assertEquals(bound.hashCode(), unbound.hashCode());
+    }
+
+    private static GenericTypes key(ImClass list, ImClassType nestedType) {
+        ImClassType listType = JassIm.ImClassType(list,
+            JassIm.ImTypeArguments(argument(nestedType, Collections.emptyMap())));
+        return new GenericTypes(List.of(argument(listType, Collections.emptyMap())));
+    }
+
+    private static ImTypeArgument argument(de.peeeq.wurstscript.jassIm.ImType type,
+                                           Map<ImTypeClassFunc, Either<ImMethod, ImFunction>> binding) {
+        return JassIm.ImTypeArgument(type, binding);
+    }
+
+    private static ImClass genericClass(String name) {
+        return JassIm.ImClass(Ast.NoExpr(), name, JassIm.ImTypeVars(JassIm.ImTypeVar("T")),
+            JassIm.ImVars(), JassIm.ImMethods(), JassIm.ImFunctions(), List.of());
+    }
+}