big code reorganization: TypeChecker record

Several big changes, that were done in tandem, and which
would be too troublesome to break into separate commits.
The goal here is to ultimately be able to break tl.tl
into multiple files (because its size started hitting
limits in both Lua 5.1 (number of upvalues) and Lua 5.4
(number of locals). Here's a high-level summary of the
changes:

* new Errors record, encapsulating error-reporting concerns;

* all Type occurrences have unique objects reporting their
  locations (no more singletons for base types such as BOOLEAN
  and INVALID);

* some enums renamed for more consistency across Gen and Feat
  options;

* TypeCheckOptions and EnvOptions tables reorganized for
  easier forwarding of options across them;

* simplifications in the various function signatures
  of the public API;

* all Types and Nodes store filename, line and column
  location (`f`, `y`, `x`);

* Scope is now a record containing the variables map and
  unresolved items -- no more "@unresolved" pseudo-variable
  and `unresolved` pseudo-type for storing this data in
  the symbols table;

* `type_check` now uses a TypeChecker object for storing all state, instead of
  relying on closures and function nesting (that's a bit sad is it ended up
  spreading `self:` and extra function arguments everywhere, but I guess state
  management will be more explicit for others reading the code now...);

* all Fact objects have a Where location as well, and supressions of
  inference data in error messages for widened-back types is marked
  explicitly with `no_infer` instead of missing a `w` field;

* general simplification of the sourcing of error locations (though
  I would still like to improve that further);

spec/api/gen_spec.lua

@@ -69,7 +69,7 @@ describe("tl.gen", function()
          print(math.floor(2))
       ]]
 
-      local env = tl.init_env(true, true)
+      local env = tl.init_env(true, false)
       local output, result = tl.gen(input, env)
 
       assert.equal('print(math.floor(2))', output)
@@ -83,7 +83,7 @@ describe("tl.gen", function()
 
 print(math.floor(2))]]
 
-      local env = tl.init_env(true, true)
+      local env = tl.init_env(true, false)
       local output, result = tl.gen(input, env)
 
       assert.equal(input, output)

spec/api/get_types_spec.lua

@@ -8,7 +8,7 @@ describe("tl.get_types", function()
          local function a()
             ::continue::
          end
-      ]], false, env))
+      ]], env))
 
       local tr, trenv = tl.get_types(result)
       assert(tr)
@@ -25,7 +25,7 @@ describe("tl.get_types", function()
          end
 
          R.f("hello")
-      ]], false, env))
+      ]], env))
 
       local tr, trenv = tl.get_types(result)
       local y = 6

spec/api/pretty_print_ast.lua

@@ -4,7 +4,7 @@ local util = require("spec.util")
 describe("tl.pretty_print_ast", function()
    it("returns error for <close> attribute on non 5.4 target", function()
       local input = [[local x <close> = io.open("foobar", "r")]]
-      local result = tl.process_string(input, false, tl.init_env(false, "off", "5.4"), "foo.tl")
+      local result = tl.process_string(input, tl.init_env(false, "off", "5.4"), "foo.tl")
       local output, err = tl.pretty_print_ast(result.ast, "5.3")
 
       assert.is_nil(output)

spec/call/generic_function_spec.lua

@@ -370,7 +370,7 @@ describe("generic function", function()
          recurse_node(ast, visit_node, visit_type)
       end
    ]], {
-      { x = 40, msg = "argument 3: in map value: type parameter <T>: got number, expected string" }
+      { y = 16, x = 40, msg = "argument 3: in map value: type parameter <T>: got number, expected string" }
    }))
 
    it("inference trickles down to function arguments, pass", util.check([[

spec/cli/types_spec.lua

@@ -199,7 +199,6 @@ describe("tl types works like check", function()
          local by_pos = types.by_pos[next(types.by_pos)]
          assert(by_pos["1"])
          assert(by_pos["1"]["13"]) -- require
-         assert(by_pos["1"]["20"]) -- (
          assert(by_pos["1"]["21"]) -- "os"
          assert(by_pos["1"]["26"]) -- .
       end)
@@ -217,18 +216,17 @@ describe("tl types works like check", function()
          assert(types.by_pos)
          local by_pos = types.by_pos[next(types.by_pos)]
          assert.same({
-            ["19"] = 2,
-            ["20"] = 5,
-            ["22"] = 2,
-            ["39"] = 6,
-            ["41"] = 2,
+            ["19"] = 8,
+            ["22"] = 8,
+            ["23"] = 6,
+            ["30"] = 2,
+            ["41"] = 8,
          }, by_pos["1"])
          assert.same({
-            ["17"] = 3,
-            ["20"] = 4,
-            ["25"] = 17,
-            ["30"] = 16,
-            ["31"] = 2,
+            ["17"] = 6,
+            ["20"] = 2,
+            ["25"] = 9,
+            ["31"] = 8,
          }, by_pos["2"])
       end)
    end)

spec/declaration/record_method_spec.lua

@@ -239,8 +239,8 @@ describe("record method", function()
          return "hello"
       end
    ]], {
-      { msg = "in assignment: incompatible number of returns: got 0 (), expected 1 (string)" },
-      { msg = "excess return values, expected 0 (), got 1 (string \"hello\")" },
+      { y = 5, msg = "in assignment: incompatible number of returns: got 0 (), expected 1 (string)" },
+      { y = 6, msg = "excess return values, expected 0 (), got 1 (string \"hello\")" },
    }))
 
    it("allows functions declared on method tables (#27)", function()

spec/parser/parser_error_spec.lua

@@ -2,7 +2,7 @@ local tl = require("tl")
 
 describe("parser errors", function()
    it("parse errors include filename", function ()
-      local result = tl.process_string("local x 1", false, nil, "foo.tl")
+      local result = tl.process_string("local x 1", nil, "foo.tl")
       assert.same("foo.tl", result.syntax_errors[1].filename, "parse errors should contain .filename property")
    end)
 
@@ -30,7 +30,7 @@ describe("parser errors", function()
       local code = [[
          local bar = require "bar"
       ]]
-      local result = tl.process_string(code, true, nil, "foo.tl")
+      local result = tl.process_string(code, nil, "foo.tl")
       assert.is_not_nil(string.match(result.env.loaded["./bar.tl"].syntax_errors[1].filename, "bar.tl$"), "errors should contain .filename property")
    end)
 end)

spec/parser/parser_spec.lua

@@ -19,6 +19,7 @@ describe("parser", function()
       assert.same({
          kind = "statements",
          tk = "$EOF$",
+         f = "",
          x = 1,
          y = 1,
          xend = 5,

spec/stdlib/require_spec.lua

@@ -401,7 +401,7 @@ describe("require", function()
       local result, err = tl.process("foo.tl")
 
       assert.same(0, #result.syntax_errors)
-      assert.same(0, #result.env.loaded["foo.tl"].type_errors)
+      assert.same({}, result.env.loaded["foo.tl"].type_errors)
       assert.same(1, #result.env.loaded["./box.tl"].type_errors)
       assert.match("cannot use operator ..", result.env.loaded["./box.tl"].type_errors[1].msg)
    end)

spec/stdlib/xpcall_spec.lua

@@ -105,7 +105,7 @@ describe("xpcall", function()
       { msg = "xyz: got boolean, expected number" }
    }))
 
-   it("type checks the message handler", util.check_type_error([[
+   it("#only type checks the message handler", util.check_type_error([[
       local function f(a: string, b: number)
       end
 

spec/util.lua

@@ -435,7 +435,7 @@ local function check(lax, code, unknowns, gen_target)
       if gen_target == "5.4" then
          gen_compat = "off"
       end
-      local result = tl.type_check(ast, { filename = "foo.lua", lax = lax, gen_target = gen_target, gen_compat = gen_compat })
+      local result = tl.type_check(ast, "foo.lua", { feat_lax = lax and "on" or "off", gen_target = gen_target, gen_compat = gen_compat })
       batch:add(assert.same, {}, result.type_errors)
 
       if unknowns then
@@ -456,7 +456,7 @@ local function check_type_error(lax, code, type_errors, gen_target)
       if gen_target == "5.4" then
          gen_compat = "off"
       end
-      local result = tl.type_check(ast, { filename = "foo.tl", lax = lax, gen_target = gen_target, gen_compat = gen_compat })
+      local result = tl.type_check(ast, "foo.tl", { feat_lax = lax and "on" or "off", gen_target = gen_target, gen_compat = gen_compat })
       local result_type_errors = combine_result(result, "type_errors")
 
       batch_compare(batch, "type errors", type_errors, result_type_errors)
@@ -525,7 +525,7 @@ function util.check_syntax_error(code, syntax_errors)
       local batch = batch_assertions()
       batch_compare(batch, "syntax errors", syntax_errors, errors)
       batch:assert()
-      tl.type_check(ast, { filename = "foo.tl", lax = false })
+      tl.type_check(ast, "foo.tl", { feat_lax = "off" })
    end
 end
 
@@ -564,7 +564,7 @@ function util.check_types(code, types)
       local batch = batch_assertions()
       local env = tl.init_env()
       env.report_types = true
-      local result = tl.type_check(ast, { filename = "foo.tl", env = env, lax = false })
+      local result = tl.type_check(ast, "foo.tl", { feat_lax = "off" }, env)
       batch:add(assert.same, {}, result.type_errors, "Code was not expected to have type errors")
 
       local tr = env.reporter:get_report()
@@ -596,7 +596,7 @@ local function gen(lax, code, expected, gen_target)
    return function()
       local ast, syntax_errors = tl.parse(code, "foo.tl")
       assert.same({}, syntax_errors, "Code was not expected to have syntax errors")
-      local result = tl.type_check(ast, { filename = "foo.tl", lax = lax, gen_target = gen_target })
+      local result = tl.type_check(ast, "foo.tl", { feat_lax = lax and "on" or "off", gen_target = gen_target })
       assert.same({}, result.type_errors)
       local output_code = tl.pretty_print_ast(ast)
 

tl

@@ -163,10 +163,12 @@ local function setup_env(tlconfig, filename)
    end
 
    local opts = {
-      lax_mode = lax_mode,
-      feat_arity = tlconfig["feat_arity"],
-      gen_compat = tlconfig["gen_compat"],
-      gen_target = tlconfig["gen_target"],
+      defaults = {
+         feat_lax = lax_mode and "on" or "off",
+         feat_arity = tlconfig["feat_arity"],
+         gen_compat = tlconfig["gen_compat"],
+         gen_target = tlconfig["gen_target"],
+      },
       predefined_modules = tlconfig._init_env_modules,
    }