fix set heap allocation and require explicit type args

.claude/rules.md

@@ -206,7 +206,8 @@ Existing bridges: `regex-bridge.c`, `yyjson-bridge.c`, `os-bridge.c`, `child-pro
 5. **Type cast field order must match FULL struct layout** — when the type extends a parent interface, the struct includes ALL parent fields. `as { name, closureInfo }` on a `LiftedFunction extends FunctionNode` (10 fields) reads index 1 instead of index 9. Include every field.
 6. **`ret void` not `unreachable`** at end of void functions
 7. **Class structs: boolean is `i1`; Interface structs: boolean is `double`**
-8. **Set feature flags when emitting gated extern calls** — runtime declarations for C bridges (yyjson, curl, etc.) are conditionally emitted behind flags like `usesJson`, `usesCurl`. Any code path that emits `call @csyyjson_*` must call `ctx.setUsesJson(true)`, etc. Missing this causes "undefined value" errors from `opt` because the `declare` is never emitted.
+8. **Propagate declared type before generating RHS for collection fields** — when a class field is typed `Set<string>`, `Map<K,V>`, etc., call `setCurrentDeclaredSetType` / `setCurrentDeclaredMapType` before `generateExpression` on the RHS so that `new Set()` / `new Map()` without explicit type args picks the right generator. See `handleClassFieldAssignment` in `assignment-generator.ts`.
+9. **Set feature flags when emitting gated extern calls** — runtime declarations for C bridges (yyjson, curl, etc.) are conditionally emitted behind flags like `usesJson`, `usesCurl`. Any code path that emits `call @csyyjson_*` must call `ctx.setUsesJson(true)`, etc. Missing this causes "undefined value" errors from `opt` because the `declare` is never emitted.
 
 ## Interface Field Iteration
 
@@ -228,7 +229,8 @@ any interface with inheritance. `allocateDeclaredInterface` does this correctly;
 1. **`new` in class field initializers** — codegen handles simple `new X()` in field initializers (both explicit and default constructors), but complex nested class instantiation may have edge cases. Prefer initializing in constructors for safety.
 2. **Type assertions must match real struct field order AND count** — `as { type, left, right }` on a struct that's `{ type, op, left, right }` causes GEP to read wrong fields. Fields must be a PREFIX of the real struct in EXACT order. **Watch out for `extends`**: if `Child extends Parent`, the struct has ALL of Parent's fields first, then Child's. A type assertion on a Child must include Parent's fields too — even optional ones the object literal doesn't set (the compiler allocates slots for them anyway, filled with null/0).
 3. **Never insert new optional fields in the MIDDLE of an interface** — The native compiler determines struct layouts from object literal creation sites. If an interface has multiple creation sites (e.g., `MethodCallNode` is created in parser-ts, parser-native, and codegen), inserting a new field before existing ones shifts GEP indices and breaks creation sites that don't include the new field. **Always add new optional fields at the END of interfaces.** Root cause: the native compiler doesn't unify struct layouts from interface definitions — it uses object literal field order, and different creation sites may have different subsets of fields.
-4. **`||` fallback makes member access opaque** — `const x = foo.bar || { field: [] }` stores the result as `i8*` (opaque pointer) because the `||` merges two different types. Subsequent `.field` access on `x` does NOT generate a GEP — it just returns `x` itself. Fix: use a ternary that preserves the typed path: `const y = foo.bar ? foo.bar.field : []`. This applies to any `||` or `??` where the fallback is an inline object literal.
+4. **`alloca` for collection structs stored in class fields** — `%Set`, `%StringSet`, `%Map`, and similar structs must be heap-allocated via `GC_malloc`, not `alloca`. Stack-allocated structs become dangling pointers when stored in a class field after the constructor returns. Use `emitCall("i8*", "@GC_malloc", "i64 N") + emitBitcast(...)` instead of `emit("... = alloca %Foo")`.
+5. **`||` fallback makes member access opaque** — `const x = foo.bar || { field: [] }` stores the result as `i8*` (opaque pointer) because the `||` merges two different types. Subsequent `.field` access on `x` does NOT generate a GEP — it just returns `x` itself. Fix: use a ternary that preserves the typed path: `const y = foo.bar ? foo.bar.field : []`. This applies to any `||` or `??` where the fallback is an inline object literal.
 
 ## Stage 0 Compatibility
 

scripts/run-examples.sh

@@ -74,7 +74,7 @@ echo ""
 
 # --- 1. hello.ts (simple print) ---
 
-echo "[1/8] hello.ts"
+echo "[1/9] hello.ts"
 if compile examples/hello.ts "$BUILD_DIR/hello"; then
   OUTPUT=$("$BUILD_DIR/hello" 2>&1) || true
   if echo "$OUTPUT" | grep -q "Hello from ChadScript"; then
@@ -88,7 +88,7 @@ fi
 
 # --- 2. timers.ts (event loop, self-terminating) ---
 
-echo "[2/8] timers.ts"
+echo "[2/9] timers.ts"
 if compile examples/timers.ts "$BUILD_DIR/timers"; then
   # No `timeout` on macOS — use background process + wait with a deadline
   "$BUILD_DIR/timers" > "$BUILD_DIR/timers.out" 2>&1 &
@@ -110,7 +110,7 @@ fi
 
 # --- 3. cli-parser-demo.ts (argparse) ---
 
-echo "[3/8] cli-parser-demo.ts"
+echo "[3/9] cli-parser-demo.ts"
 if compile examples/cli-parser-demo.ts "$BUILD_DIR/cli-parser-demo"; then
   OUTPUT=$("$BUILD_DIR/cli-parser-demo" -v -o result.txt myfile.txt 2>&1) || true
   if echo "$OUTPUT" | grep -q "verbose"; then
@@ -124,7 +124,7 @@ fi
 
 # --- 4. query.ts (sqlite in-memory) ---
 
-echo "[4/8] query.ts"
+echo "[4/9] query.ts"
 if compile examples/query.ts "$BUILD_DIR/query"; then
   OUTPUT=$("$BUILD_DIR/query" 2>&1) || true
   if echo "$OUTPUT" | grep -q "Found"; then
@@ -138,7 +138,7 @@ fi
 
 # --- 5. word-count.ts (file I/O) ---
 
-echo "[5/8] word-count.ts"
+echo "[5/9] word-count.ts"
 if compile examples/word-count.ts "$BUILD_DIR/word-count"; then
   # Create a test file to count
   echo "hello world foo bar" > "$BUILD_DIR/test-input.txt"
@@ -154,7 +154,7 @@ fi
 
 # --- 6. string-search.ts (grep-like) ---
 
-echo "[6/8] string-search.ts"
+echo "[6/9] string-search.ts"
 if compile examples/string-search.ts "$BUILD_DIR/string-search"; then
   # Create a test file to search
   printf "line one\nfind me here\nline three\n" > "$BUILD_DIR/search-input.txt"
@@ -170,7 +170,7 @@ fi
 
 # --- 7. http-server.ts (server + curl) ---
 
-echo "[7/8] http-server.ts"
+echo "[7/9] http-server.ts"
 if compile examples/http-server.ts "$BUILD_DIR/http-server"; then
   PORT=18080
   "$BUILD_DIR/http-server" -p "$PORT" &
@@ -208,7 +208,7 @@ fi
 
 # --- 8. hackernews/app.ts (full-stack server + curl) ---
 
-echo "[8/8] hackernews/app.ts"
+echo "[8/9] hackernews/app.ts"
 if compile examples/hackernews/app.ts "$BUILD_DIR/hackernews"; then
   PORT=18081
   "$BUILD_DIR/hackernews" -p "$PORT" &
@@ -238,6 +238,27 @@ else
   fail "hackernews/app.ts" "compile failed"
 fi
 
+# --- 9. parallel.ts (parallel HTTP fetches with Promise.all) ---
+
+echo "[9/9] parallel.ts"
+if compile examples/parallel.ts "$BUILD_DIR/parallel"; then
+  "$BUILD_DIR/parallel" > "$BUILD_DIR/parallel.out" 2>&1 &
+  PARALLEL_PID=$!
+  ( sleep 30; kill "$PARALLEL_PID" 2>/dev/null ) &
+  WATCHDOG_PID=$!
+  wait "$PARALLEL_PID" 2>/dev/null || true
+  kill "$WATCHDOG_PID" 2>/dev/null || true
+  wait "$WATCHDOG_PID" 2>/dev/null || true
+  OUTPUT=$(cat "$BUILD_DIR/parallel.out")
+  if echo "$OUTPUT" | grep -q "stars"; then
+    pass "parallel.ts"
+  else
+    fail "parallel.ts" "unexpected output: $OUTPUT"
+  fi
+else
+  fail "parallel.ts" "compile failed"
+fi
+
 # --- Summary ---
 
 echo ""

src/codegen/expressions/literals.ts

@@ -185,7 +185,12 @@ export class LiteralExpressionGenerator {
       return this.generateNewRegExp(args, params);
     }
     if (className === "Set") {
-      if (typeArgs && typeArgs.length > 0 && typeArgs[0] === "string") {
+      if (!typeArgs || typeArgs.length === 0) {
+        throw new Error(
+          "new Set() requires an explicit type argument, e.g. new Set<string>() or new Set<number>()",
+        );
+      }
+      if (typeArgs[0] === "string") {
         return this.ctx.stringSetGen.generateEmptyStringSet();
       }
       return this.ctx.setGen.generateSetLiteral({ type: "set", values: [] }, params);

src/codegen/infrastructure/assignment-generator.ts

@@ -45,6 +45,8 @@ export interface AssignmentGeneratorContext {
   setExpectedArrayElementType(type: "string" | "number" | "boolean" | "pointer" | null): void;
   currentDeclaredMapType: string | undefined;
   setCurrentDeclaredMapType(type: string | undefined): void;
+  currentDeclaredSetType: string | undefined;
+  setCurrentDeclaredSetType(type: string | undefined): void;
   getThisPointer(): string | null;
   getCurrentClassName(): string | null;
   readonly symbolTable: SymbolTable;
@@ -249,9 +251,14 @@ export class AssignmentGenerator {
       this.ctx.setCurrentDeclaredMapType(fieldTsType);
     }
 
+    if (fieldTsType && fieldTsType.startsWith("Set<")) {
+      this.ctx.setCurrentDeclaredSetType(fieldTsType);
+    }
+
     const value = this.ctx.generateExpression(memberAccessValue.value, params);
     this.ctx.setExpectedArrayElementType(null);
     this.ctx.setCurrentDeclaredMapType(undefined);
+    this.ctx.setCurrentDeclaredSetType(undefined);
 
     let instancePtr: string | null = null;
     const objType = object.type;

src/codegen/types/collections/set.ts

@@ -34,9 +34,9 @@ export class SetGenerator {
       throw new Error("Expected set literal");
     }
 
-    // Allocate Set struct on stack
-    const setPtr = this.nextTemp();
-    this.emit(`${setPtr} = alloca %Set`);
+    // Allocate Set struct on heap so it's safe to store in class fields
+    const setMem = this.ctx.emitCall("i8*", "@GC_malloc", `i64 16`);
+    const setPtr = this.ctx.emitBitcast(setMem, "i8*", "%Set*");
 
     // Initialize with empty array
     const initialCapacity = setExpr.values.length > 4 ? setExpr.values.length : 4;
@@ -390,8 +390,9 @@ export class StringSetGenerator {
   }
 
   generateEmptyStringSet(): string {
-    const setPtr = this.nextTemp();
-    this.emit(`${setPtr} = alloca %StringSet`);
+    // Allocate StringSet struct on heap so it's safe to store in class fields
+    const setMem = this.ctx.emitCall("i8*", "@GC_malloc", `i64 16`);
+    const setPtr = this.ctx.emitBitcast(setMem, "i8*", "%StringSet*");
 
     const initialCapacity = 4;
     const ptrSize = this.getPtrSize();