fix(typechecker): verify map type is well-formed (#704)

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Returning `self` from getters is now allowed: PR [#666](https://github.com/tact-lang/tact/pull/666)
 - Remainder fields in the middle of a struct are now forbidden: PR [#697](https://github.com/tact-lang/tact/pull/697)
 - Defining two native functions from the same FunC function now does not fail compilation: PR [#699](https://github.com/tact-lang/tact/pull/699)
+- Map types are checked for well-formedness in all type ascriptions: PR [#704](https://github.com/tact-lang/tact/pull/704)
 
 ## [1.4.3] - 2024-08-16
 

cspell.json

@@ -23,6 +23,7 @@
     "elseifnot",
     "Fift",
     "forall",
+    "formedness",
     "funs",
     "funcfiftlib",
     "funcid",

src/types/__snapshots__/resolveDescriptors.spec.ts.snap

@@ -486,6 +486,56 @@ Line 7, col 1:
 "
 `;
 
+exports[`resolveDescriptors should fail descriptors for wf-type-const 1`] = `
+"<unknown>:4:19: Invalid key type for map. Check https://docs.tact-lang.org/book/maps#allowed-types
+Line 4, col 19:
+  3 | 
+> 4 | const m: map<Int, String> = null;
+                        ^~~~~~
+  5 | 
+"
+`;
+
+exports[`resolveDescriptors should fail descriptors for wf-type-contract-const 1`] = `
+"<unknown>:6:23: Invalid key type for map. Check https://docs.tact-lang.org/book/maps#allowed-types
+Line 6, col 23:
+  5 | contract Test {
+> 6 |     const m: map<Int, String> = null;
+                            ^~~~~~
+  7 | }
+"
+`;
+
+exports[`resolveDescriptors should fail descriptors for wf-type-contract-const-incorrect-annotation 1`] = `
+"<unknown>:6:34: "Address" type cannot have as-annotation
+Line 6, col 34:
+  5 | contract Test {
+> 6 |     const m: map<Int, Address as uint32> = null;
+                                       ^~~~~~
+  7 | }
+"
+`;
+
+exports[`resolveDescriptors should fail descriptors for wf-type-contract-getter 1`] = `
+"<unknown>:6:29: Invalid key type for map. Check https://docs.tact-lang.org/book/maps#allowed-types
+Line 6, col 29:
+  5 | contract Test {
+> 6 |     get fun foo(): map<Int, String> {
+                                  ^~~~~~
+  7 |         let m: map<Int, String> = null;
+"
+`;
+
+exports[`resolveDescriptors should fail descriptors for wf-type-fun-param 1`] = `
+"<unknown>:4:16: Invalid key type for map. Check https://docs.tact-lang.org/book/maps#allowed-types
+Line 4, col 16:
+  3 | 
+> 4 | fun foo(m: map<Bool, Int>) { }
+                     ^~~~
+  5 | 
+"
+`;
+
 exports[`resolveDescriptors should resolve descriptors for const-decl-struct-with-default-field 1`] = `
 {
   "BaseTrait": {

src/types/__snapshots__/resolveStatements.spec.ts.snap

@@ -1205,6 +1205,16 @@ Line 9, col 12:
 "
 `;
 
+exports[`resolveStatements should fail statements for wf-type-let 1`] = `
+"<unknown>:5:16: Invalid key type for map. Check https://docs.tact-lang.org/book/maps#allowed-types
+Line 5, col 16:
+  4 | fun foo() {
+> 5 |     let m: map<String, Int> = null;
+                     ^~~~~~
+  6 | }
+"
+`;
+
 exports[`resolveStatements should resolve statements for assign-self-mutating-method 1`] = `
 [
   [