[Tolk] Rewrite the type system from Hindley-Milner to static typing

FunC's (and Tolk's before this PR) type system is based on Hindley-Milner.
This is a common approach for functional languages, where
types are inferred from usage through unification.
As a result, type declarations are not necessary:
() f(a,b) { return a+b; } // a and b now int, since `+` (int, int)

While this approach works for now, problems arise with the introduction
of new types like bool, where `!x` must handle both int and bool.
It will also become incompatible with int32 and other strict integers.
This will clash with structure methods, struggle with proper generics,
and become entirely impractical for union types.

This PR completely rewrites the type system targeting the future.
1) type of any expression is inferred and never changed
2) this is available because dependent expressions already inferred
3) forall completely removed, generic functions introduced
   (they work like template functions actually, instantiated while inferring)
4) instantiation `<...>` syntax, example: `t.tupleAt<int>(0)`
5) `as` keyword, for example `t.tupleAt(0) as int`
6) methods binding is done along with type inferring, not before
   ("before", as worked previously, was always a wrong approach)

Author: tolk-vm

crypto/smartcont/tolk-stdlib/common.tolk

@@ -17,17 +17,17 @@ fun createEmptyTuple(): tuple
 /// Appends a value to tuple, resulting in `Tuple t' = (x1, ..., xn, value)`.
 /// If its size exceeds 255, throws a type check exception.
 @pure
-fun tuplePush<X>(mutate self: tuple, value: X): void
+fun tuplePush<T>(mutate self: tuple, value: T): void
     asm "TPUSH";
 
 /// Returns the first element of a non-empty tuple.
 @pure
-fun tupleFirst<X>(t: tuple): X
+fun tupleFirst<T>(t: tuple): T
     asm "FIRST";
 
 /// Returns the [`index`]-th element of a tuple.
 @pure
-fun tupleAt<X>(t: tuple, index: int): X
+fun tupleAt<T>(t: tuple, index: int): T
     builtin;
 
 /// Returns the size of a tuple (elements count in it).
@@ -37,7 +37,7 @@ fun tupleSize(t: tuple): int
 
 /// Returns the last element of a non-empty tuple.
 @pure
-fun tupleLast(t: tuple): int
+fun tupleLast<T>(t: tuple): T
     asm "LAST";
 
 
@@ -306,11 +306,11 @@ fun getBuilderDepth(b: builder): int
  */
 
 /// Dump a variable [x] to the debug log.
-fun debugPrint<X>(x: X): void
+fun debugPrint<T>(x: T): void
     builtin;
 
 /// Dump a string [x] to the debug log.
-fun debugPrintString<X>(x: X): void
+fun debugPrintString<T>(x: T): void
     builtin;
 
 /// Dumps the stack (at most the top 255 values) and shows the total stack depth.

crypto/smartcont/tolk-stdlib/gas-payments.tolk

@@ -61,3 +61,9 @@ fun calculateOriginalMessageFee(workchain: int, incomingFwdFee: int): int
 /// If it has no debt, `0` is returned.
 fun getMyStorageDuePayment(): int
     asm "DUEPAYMENT";
+
+/// Returns the amount of nanotoncoins charged for storage.
+/// (during storage phase preceeding to current computation phase)
+@pure
+fun getMyStoragePaidPayment(): int
+    asm "STORAGEFEES";

tolk-tester/tests/a10.tolk

@@ -35,7 +35,7 @@ fun test88(x: int) {
 }
 
 @method_id(89)
-fun test89(last: int) {
+fun test89(last: int): (int, int, int, int) {
     var t: tuple = createEmptyTuple();
     t.tuplePush(1);
     t.tuplePush(2);

tolk-tester/tests/a6.tolk

@@ -9,6 +9,7 @@ fun calc_phi(): int {
   repeat (70) { n*=10; };
   var p= 1;
   var `q`=1;
+  _=`q`;
   do {
     (p,q)=(q,p+q);
   } while (q <= n); //;;
@@ -27,7 +28,7 @@ fun calc_sqrt2(): int {
   return mulDivRound(p, n, q);
 }
 
-fun calc_root(m: auto): auto {
+fun calc_root(m: int) {
   var base: int=1;
   repeat(70) { base *= 10; }
   var (a, b, c) = (1,0,-m);

tolk-tester/tests/a6_5.tolk

@@ -1,5 +1,5 @@
 @deprecated
-fun twice(f: auto, x: auto): auto {
+fun twice(f: int -> int, x: int) {
   return f (f (x));
 }
 

tolk-tester/tests/allow_post_modification.tolk

@@ -138,5 +138,5 @@ fun main() {
     inc CALLDICT // self newY
   }>
 """
-@code_hash 33262590582878205026101577472505372101182291690814957175155528952950621243206
+@code_hash 7627024945492125068389905298530400936797031708759561372406088054030801992712
 */

tolk-tester/tests/assignment-tests.tolk

@@ -0,0 +1,28 @@
+fun extractFromTypedTuple(params: [int]) {
+    var [payload: int] = params;
+    return payload + 10;
+}
+
+@method_id(101)
+fun test101(x: int) {
+    var params = [x];
+    return extractFromTypedTuple(params);
+}
+
+fun autoInferIntNull(x: int) {
+    if (x > 10) { return null; }
+    return x;
+}
+
+fun main(value: int) {
+    var (x: int, y) = (autoInferIntNull(value), autoInferIntNull(value * 2));
+    if (x == null && y == null) { return null; }
+    return x == null || y == null ? -1 : x + y;
+}
+
+/**
+@testcase | 0   | 3      | 9
+@testcase | 0   | 6      | -1
+@testcase | 0   | 11     | (null)
+@testcase | 101 | 78     | 88
+*/

tolk-tester/tests/c2.tolk

@@ -4,7 +4,7 @@ fun check_assoc(a: int, b: int, c: int): int {
   return op(op(a, b), c) == op(a, op(b, c));
 }
 
-fun unnamed_args(_: int, _: slice, _: auto): auto {
+fun unnamed_args(_: int, _: slice, _: int) {
   return true;
 }
 
@@ -14,7 +14,7 @@ fun main(x: int, y: int, z: int): int {
 }
 
 @method_id(101)
-fun test101(x: int, z: int): auto {
+fun test101(x: int, z: int) {
   return unnamed_args(x, "asdf", z);
 }
 

tolk-tester/tests/c2_1.tolk

@@ -1,4 +1,4 @@
-fun check_assoc(op: auto, a: int, b: int, c: int) {
+fun check_assoc(op: (int, int) -> int, a: int, b: int, c: int) {
   return op(op(a, b), c) == op(a, op(b, c));
 }
 

tolk-tester/tests/generics-1.tolk

@@ -0,0 +1,150 @@
+fun eq1<X>(value: X): X { return value; }
+fun eq2<X>(value: X)    { return value; }
+fun eq3<X>(value: X): X { var cp: [X] = [eq1(value)]; var ((([v: X]))) = cp; return v; }
+fun eq4<X>(value: X)    { return eq1<X>(value); }
+
+@method_id(101)
+fun test101(x: int) {
+    var (a, b, c) = (x, (x,x), [x,x]);
+    return (eq1(a), eq1(b), eq1(c), eq2(a), eq2(b), eq2(c), eq3(a), eq4(b), eq3(createEmptyTuple()));
+}
+
+fun getTwo<X>(): X { return 2 as X; }
+
+fun takeInt(a: int) { return a; }
+
+@method_id(102)
+fun test102(): (int, int, int, [(int, int)]) {
+    var a: int = getTwo();
+    var _: int = getTwo();
+    var b = getTwo() as int;
+    var c: int = 1 ? getTwo() : getTwo();
+    var c redef = getTwo();
+    return (eq1<int>(a), eq2<int>(b), takeInt(getTwo()), [(getTwo(), getTwo())]);
+}
+
+@method_id(103)
+fun test103(first: int): (int, int, int) {
+    var t = createEmptyTuple();
+    var cs = beginCell().storeInt(100, 32).endCell().beginParse();
+    t.tuplePush(first);
+    t.tuplePush(2);
+    t.tuplePush(cs);
+    cs = t.tupleAt(2);
+    cs = t.tupleAt(2) as slice;
+    return (t.tupleAt(0), cs.loadInt(32), t.tupleAt<slice>(2).loadInt(32));
+}
+
+fun manyEq<T1, T2, T3>(a: T1, b: T2, c: T3): [T1, T2, T3] {
+    return [a, b, c];
+}
+
+@method_id(104)
+fun test104(f: int) {
+    return (
+        manyEq(1 ? 1 : 1, f ? 0 : null, !f ? getTwo() as int : null),
+        manyEq((f ? null as int : eq2(2), beginCell().storeBool(true).endCell().beginParse().loadBool()), 0, eq4(f))
+    );
+}
+
+fun calcSum<X>(x: X, y: X) { return x + y; }
+
+@method_id(105)
+fun test105() {
+    if (0) { calcSum(((0)), null); }
+    return (calcSum(1, 2));
+}
+
+fun calcYPlus1<Y>(value: Y) { return value + 1; }
+fun calcLoad32(cs: slice) { return cs.loadInt(32); }
+fun calcTensorPlus1(tens: (int, int)) { var (f, s) = tens; return (f + 1, s + 1); }
+fun calcTensorMul2(tens: (int, int)) { var (f, s) = tens; return (f * 2, s * 2); }
+fun cellToSlice(c: cell) { return c.beginParse(); }
+fun abstractTransform<X, Y, R>(xToY: (X) -> Y, yToR: (((Y))) -> R, initialX: X): R {
+    var y = xToY(initialX);
+    return yToR(y);
+}
+
+@method_id(106)
+fun test106() {
+    var c = beginCell().storeInt(106, 32).endCell();
+    return [
+        abstractTransform(cellToSlice, calcLoad32, c),
+        abstractTransform(calcYPlus1<int>, calcYPlus1<int>, 0),
+        abstractTransform(calcTensorPlus1, calcTensorMul2, (2, 2))
+    ];
+}
+
+fun callTupleFirst<X, Y>(t: X): Y { return t.tupleFirst(); }
+fun callTuplePush<T, V>(mutate self: T, v1: V, v2: V): self { self.tuplePush(v1); tuplePush(mutate self, v2); return self; }
+fun getTupleLastInt(t: tuple) { return t.tupleLast<int>(); }
+fun getTupleSize(t: tuple) { return t.tupleSize(); }
+fun callAnyFn<TObj, TResult>(f: (TObj) -> TResult, arg: TObj) { return f(arg); }
+fun callAnyFn2<TCallback>(f: TCallback, arg: tuple) { return f(arg); }
+
+global t107: tuple;
+
+@method_id(107)
+fun test107() {
+    t107 = createEmptyTuple();
+    callTuplePush(mutate t107, 1, 2);
+    t107.callTuplePush(3, 4).callTuplePush(5, 6);
+    var first: int = t107.callTupleFirst();
+    return (
+        callAnyFn<tuple, int>(getTupleSize, t107),
+        callAnyFn2(getTupleSize, t107),
+        first,
+        callTupleFirst(t107) as int,
+        callAnyFn(getTupleLastInt, t107),
+        callAnyFn2(getTupleLastInt, t107)
+    );
+}
+
+global g108: int;
+
+fun inc108(by: int) { g108 += by; }
+fun getInc108() { return inc108; }
+fun returnResult<RetT>(f: () -> RetT): RetT { return f(); }
+fun applyAndReturn<ArgT, RetT>(f: () -> (ArgT) -> RetT, arg: ArgT): () -> ArgT -> RetT {
+    f()(arg);
+    return f;
+}
+
+@method_id(108)
+fun test108() {
+    g108 = 0;
+    getInc108()(1);
+    returnResult<(int) -> void>(getInc108)(2);
+    applyAndReturn<int, void>(getInc108, 10)()(10);
+    returnResult(getInc108)(2);
+    applyAndReturn(getInc108, 10)()(10);
+    return g108;
+}
+
+fun main(x: int): (int, [[int, int]]) {
+    try { if(x) { throw (1, x); } }
+    catch (excNo, arg) { return (arg as int, [[eq2(arg as int), getTwo()]]); }
+    return (0, [[x, 1]]);
+}
+
+/**
+@testcase | 0   | 1 | 1 [ [ 1 2 ] ]
+@testcase | 101 | 0 | 0 0 0 [ 0 0 ] 0 0 0 [ 0 0 ] 0 0 0 []
+@testcase | 102 |   | 2 2 2 [ 2 2 ]
+@testcase | 103 | 0 | 0 100 100
+@testcase | 104 | 0 | [ 1 (null) 2 ] [ 2 -1 0 0 ]
+@testcase | 105 |   | 3
+@testcase | 106 |   | [ 106 2 6 6 ]
+@testcase | 107 |   | 6 6 1 1 6 6
+@testcase | 108 |   | 45
+
+@fif_codegen DECLPROC eq1<int>
+@fif_codegen DECLPROC eq1<tuple>
+@fif_codegen DECLPROC eq1<(int,int)>
+@fif_codegen DECLPROC eq1<[int,int]>
+@fif_codegen DECLPROC getTwo<int>
+
+@fif_codegen_avoid DECLPROC eq1
+@fif_codegen_avoid DECLPROC eq2
+@fif_codegen_avoid DECLPROC eq3
+ */