feat: Simplify pointer semantics

compiler/test/suites/basic_functionality.re

@@ -377,6 +377,6 @@ describe("basic functionality", ({test, testSkip}) => {
     ~config_fn=smallestFileConfig,
     "smallest_grain_program",
     "",
-    6503,
+    6494,
   );
 });

stdlib/runtime/gc.gr

@@ -25,6 +25,7 @@ from "runtime/unsafe/panic" include Panic
 from "runtime/unsafe/wasmi32" include WasmI32
 use WasmI32.{ (+), (-), (*), (&), (==), (!=) }
 
+primitive (!) = "@not"
 primitive (&&) = "@and"
 primitive (||) = "@or"
 primitive ignore = "@ignore"
@@ -75,7 +76,7 @@ provide let incRef = (userPtr: WasmI32) => {
   userPtr
 }
 
-let rec decRef = (userPtr: WasmI32, parentPtr: WasmI32, ignoreZeros: Bool) => {
+let rec decRef = (userPtr: WasmI32, ignoreZeros: Bool) => {
   if (WasmI32.eqz(userPtr & Tags._GRAIN_GENERIC_TAG_MASK) && userPtr != 0n) {
     let refCount = getRefCount(userPtr)
     // if (_DEBUG) {
@@ -84,9 +85,7 @@ let rec decRef = (userPtr: WasmI32, parentPtr: WasmI32, ignoreZeros: Bool) => {
     // }
 
     if (WasmI32.eqz(refCount)) {
-      if (ignoreZeros) {
-        parentPtr
-      } else {
+      if (!ignoreZeros) {
         throwDecRefError()
       }
     } else {
@@ -100,58 +99,50 @@ let rec decRef = (userPtr: WasmI32, parentPtr: WasmI32, ignoreZeros: Bool) => {
          *       empty blocks and does not actually zero out the memory.
          */
         free(userPtr)
-        decRefChildren(userPtr, parentPtr)
-      } else {
-        parentPtr
+        decRefChildren(userPtr)
       }
     }
-  } else {
-    parentPtr
   }
 }
 and decRefChildrenHelp = (
   userPtr: WasmI32,
-  parentPtr: WasmI32,
   arityOffset: WasmI32,
   offset: WasmI32,
 ) => {
   let arity = WasmI32.load(userPtr, arityOffset)
   if (arity != 0n) {
     let maxOffset = (arity - 1n) * 4n
     for (let mut i = 0n; WasmI32.ltU(i, maxOffset); i += 4n) {
-      ignore(decRef(WasmI32.load(userPtr + i, offset), parentPtr, false))
+      decRef(WasmI32.load(userPtr + i, offset), false)
     }
-    decRef(WasmI32.load(userPtr + maxOffset, offset), parentPtr, false)
-  } else {
-    parentPtr
+    decRef(WasmI32.load(userPtr + maxOffset, offset), false)
   }
 }
-and decRefChildren = (userPtr: WasmI32, parentPtr: WasmI32) => {
+and decRefChildren = (userPtr: WasmI32) => {
   match (WasmI32.load(userPtr, 0n)) {
     t when t == Tags._GRAIN_BOXED_NUM_HEAP_TAG => {
       let tag = WasmI32.load(userPtr, 4n)
       if (userPtr == Tags._GRAIN_RATIONAL_BOXED_NUM_TAG) {
         // decRef underlying BigInts
-        ignore(decRef(WasmI32.load(userPtr, 8n), parentPtr, false))
-        ignore(decRef(WasmI32.load(userPtr, 12n), parentPtr, false))
+        decRef(WasmI32.load(userPtr, 8n), false)
+        decRef(WasmI32.load(userPtr, 12n), false)
       }
-      parentPtr
     },
     t when t == Tags._GRAIN_ADT_HEAP_TAG => {
-      decRefChildrenHelp(userPtr, parentPtr, 16n, 20n)
+      decRefChildrenHelp(userPtr, 16n, 20n)
     },
-    t when t == Tags._GRAIN_RECORD_HEAP_TAG => {
-      decRefChildrenHelp(userPtr, parentPtr, 12n, 16n)
+    t when t == Tags._GRAIN_RECORD_HEAP_TAG || t == Tags._GRAIN_LAMBDA_HEAP_TAG => {
+      decRefChildrenHelp(userPtr, 12n, 16n)
     },
     t when t == Tags._GRAIN_ARRAY_HEAP_TAG || t == Tags._GRAIN_TUPLE_HEAP_TAG => {
-      decRefChildrenHelp(userPtr, parentPtr, 4n, 8n)
-    },
-    t when t == Tags._GRAIN_LAMBDA_HEAP_TAG => {
-      decRefChildrenHelp(userPtr, parentPtr, 12n, 16n)
+      decRefChildrenHelp(userPtr, 4n, 8n)
     },
     // No travelsal necessary for other tags
-    _ => parentPtr,
+    _ => void,
   }
 }
 
-provide let decRef = userPtr => decRef(userPtr, userPtr, false)
+provide let decRef = userPtr => {
+  decRef(userPtr, false)
+  userPtr
+}