[Tolk] Better error messages on type mismatch

For example, when passing `bits8` to `slice`, the compiler
now suggests to use `as` operator.

Author: tolk-vm

tolk-tester/tests/assignment-tests.tolk

@@ -249,6 +249,14 @@ fun test118(x: int) {
     return (i1, i2, st.owner.remainingBitsCount(), i3.0);
 }
 
+@method_id(119)
+fun test119(a: int, b: int) {
+    var t: tuple = [a + 1, b * 2] as tuple;
+    val l = t.size();
+    val [c,d:int] = [t.0 as int, t.1];
+    return (l, c, d);
+}
+
 
 
 fun main(value: int, ) {
@@ -279,6 +287,7 @@ fun main(value: int, ) {
 @testcase | 116 |        | 1 2 3 4 [ 1 2 3 4 ]
 @testcase | 117 |        | [ 20 ]
 @testcase | 118 | 3      | 10 3 0 1
+@testcase | 119 | 1 2    | 2 2 4
 
 
 @fif_codegen

tolk-tester/tests/invalid-typing/err-6010.tolk

@@ -0,0 +1,12 @@
+fun analyze(t: slice) {}
+
+fun main(t: slice?) {
+    analyze(t);
+}
+
+/**
+@compilation_should_fail
+@stderr can not pass `slice?` to `slice`
+@stderr hint: probably, you should check on null
+@stderr hint: alternatively, use `!` operator to bypass nullability checks: `<some_expr>!`
+ */

tolk-tester/tests/invalid-typing/err-6087.tolk

@@ -6,4 +6,5 @@ fun cantAutoCastBytesNToSlice() {
 /**
 @compilation_should_fail
 @stderr method `loadInt` not found for type `bits32`
+@stderr but it exists for type `slice`
  */

tolk-tester/tests/invalid-typing/err-6135.tolk

@@ -8,4 +8,5 @@ fun cantAssignIntNToCoins(n: int8, c: coins) {
 @compilation_should_fail
 @stderr can not assign `coins` to variable of type `int8`
 @stderr n = c;
+@stderr hint: use `as` operator for unsafe casting: `<some_expr> as int8`
  */

tolk-tester/tests/invalid-typing/err-6249.tolk

@@ -7,4 +7,5 @@ fun cantUnifyBytesNAndSlice(n: slice, c: bytes16) {
 /**
 @compilation_should_fail
 @stderr types of ternary branches are incompatible: `slice` and `bytes16`
+@stderr hint: maybe, you should use `<some_expr> as <type>` to make them identical
  */

tolk-tester/tests/invalid-typing/err-6390.tolk

@@ -0,0 +1,8 @@
+fun main(k: (int, slice)) {
+    var (a, b, c: int?) = k;
+}
+
+/**
+@compilation_should_fail
+@stderr can not assign `(int, slice)`, sizes mismatch
+ */

tolk-tester/tests/invalid-typing/err-6595.tolk

@@ -0,0 +1,10 @@
+fun main() {
+    blockchain.configParam(true);
+}
+
+/**
+@compilation_should_fail
+@stderr can not pass `bool` to `int`
+@stderr hint: use `as` operator for unsafe casting: `<some_expr> as int`
+@stderr caution! in TVM, bool TRUE is -1, not 1
+ */

tolk-tester/tests/invalid-typing/err-6603.tolk

@@ -0,0 +1,14 @@
+struct A {
+    kk: tuple
+    dd: [int, int]
+}
+
+fun main(a: A) {
+    a.kk = a.dd
+}
+
+/**
+@compilation_should_fail
+@stderr can not assign `[int, int]` to field of type `tuple`
+@stderr hint: use `as` operator for unsafe casting: `<some_expr> as tuple`
+ */

tolk-tester/tests/invalid-typing/err-6633.tolk

@@ -0,0 +1,11 @@
+fun main(c: cell) {
+    var sender_address: slice = c.beginParse().loadAddress();
+}
+
+/**
+@compilation_should_fail
+@stderr can not assign `address` to variable of type `slice`
+@stderr hint: unlike FunC, Tolk has a special type `address` (which is slice at the TVM level);
+@stderr most likely, you just need `address` everywhere
+@stderr hint: alternatively, use `as` operator for unsafe casting: `<some_expr> as slice`
+ */

tolk-tester/tests/invalid-typing/err-6716.tolk

@@ -0,0 +1,7 @@
+fun f(d: bits8 = "") {}
+
+/**
+@compilation_should_fail
+@stderr can not assign `slice` to `bits8`
+@stderr hint: use `as` operator for unsafe casting: `<some_expr> as bits8`
+ */