local type require() accepts dot notation for nested record

`local type MyType = require("module").MyType` is now valid.

Closes #778.

spec/cli/types_spec.lua

@@ -110,6 +110,17 @@ describe("tl types works like check", function()
          util.assert_popen_close(0, pd:close())
          -- TODO check json output
       end)
+
+      it("does not crash when a require() expression does not resolve (#778)", function()
+         local name = util.write_tmp_file(finally, [[
+            local type Foo = require("bla").baz
+         ]])
+         local pd = io.popen(util.tl_cmd("types", name, "--gen-target=5.1") .. "2>&1 1>" .. util.os_null, "r")
+         local output = pd:read("*a")
+         util.assert_popen_close(1, pd:close())
+         assert.match("1 syntax error:", output, 1, true)
+         -- TODO check json output
+      end)
    end)
 
    describe("on .lua files", function()

spec/stdlib/require_spec.lua

@@ -1152,4 +1152,55 @@ describe("require", function()
          assert.same({}, result.env.loaded["./types/person.tl"].type_errors)
       end)
    end)
+
+   it("in 'local type' accepts dots for extracting nested types", function ()
+      -- ok
+      util.mock_io(finally, {
+         ["mod.tl"] = [[
+            local record mod
+               record Foo<K>
+                  something: K
+               end
+            end
+
+            return mod
+         ]],
+         ["main.tl"] = [[
+            local type Foo = require("mod").Foo
+            local function f(v: Foo)
+               print(v.something)
+            end
+         ]],
+      })
+      local result, err = tl.process("main.tl")
+
+      assert.same({}, result.syntax_errors)
+      assert.same({}, result.type_errors)
+   end)
+
+   it("in 'local type' does not accept arbitrary expressions", function ()
+      -- ok
+      util.mock_io(finally, {
+         ["mod.tl"] = [[
+            local record mod
+               record Foo<K>
+                  something: K
+               end
+            end
+
+            return mod
+         ]],
+         ["main.tl"] = [[
+            local type Foo = require("mod") + "hello"
+            local function f(v: Foo)
+               print(v.something)
+            end
+         ]],
+      })
+      local result, err = tl.process("main.tl")
+
+      assert.same({
+         { filename = "main.tl", x = 30, y = 1, msg = "require() in type declarations cannot be part of larger expressions" }
+      }, result.syntax_errors)
+   end)
 end)

tl.lua

@@ -2808,18 +2808,25 @@ do
    end
 
    local function node_is_require_call(n)
-      if n.e1 and n.e2 and
-         n.e1.kind == "variable" and n.e1.tk == "require" and
+      if not (n.e1 and n.e2) then
+         return nil
+      end
+      if n.op and n.op.op == "." then
+
+         return node_is_require_call(n.e1)
+      elseif n.e1.kind == "variable" and n.e1.tk == "require" and
          n.e2.kind == "expression_list" and #n.e2 == 1 and
          n.e2[1].kind == "string" then
 
+
          return n.e2[1].conststr
       elseif n.op and n.op.op == "@funcall" and
          n.e1 and n.e1.tk == "pcall" and
          n.e2 and #n.e2 == 2 and
          n.e2[1].kind == "variable" and n.e2[1].tk == "require" and
          n.e2[2].kind == "string" and n.e2[2].conststr then
 
+
          return n.e2[2].conststr
       else
          return nil
@@ -4031,11 +4038,20 @@ do
 
       if ps.tokens[i].kind == "identifier" and ps.tokens[i].tk == "require" then
          local istart = i
-         i, asgn.value = parse_call_or_assignment(ps, i)
-         if asgn.value and not node_is_require_call(asgn.value) then
-            fail(ps, istart, "require() for type declarations must have a literal argument")
+         i, asgn.value = parse_expression(ps, i)
+         if asgn.value then
+            if asgn.value.op and asgn.value.op.op ~= "@funcall" and asgn.value.op.op ~= "." then
+               fail(ps, istart, "require() in type declarations cannot be part of larger expressions")
+               return i
+            end
+            if not node_is_require_call(asgn.value) then
+               fail(ps, istart, "require() for type declarations must have a literal argument")
+               return i
+            end
+            return i, asgn
+         else
+            return i
          end
-         return i, asgn
       end
 
       i, asgn.value = parse_newtype(ps, i)
@@ -10577,6 +10593,24 @@ self:expand_type(node, values, elements) })
          ty = (ty.typename == "typealias") and self:resolve_typealias(ty) or ty
          local td = (ty.typename == "typedecl") and ty or a_type(value, "typedecl", { def = ty })
          return td
+      elseif value.kind == "op" and
+         value.op.op == "." then
+
+         local ty = self:get_typedecl(value.e1)
+         if ty.typename == "typedecl" then
+            local def = ty.def
+            if def.typename == "record" then
+               local t = def.fields[value.e2.tk]
+               if t then
+                  return a_type(value, "typedecl", { def = t })
+               else
+                  return self.errs:invalid_at(value.e2, "type not found")
+               end
+            else
+               return self.errs:invalid_at(value.e2, "type is not a record")
+            end
+         end
+         return ty
       else
          local newtype = value.newtype
          if newtype.typename == "typealias" then

tl.tl

@@ -2808,18 +2808,25 @@ local function parse_literal(ps: ParseState, i: integer): integer, Node
 end
 
 local function node_is_require_call(n: Node): string
-   if n.e1 and n.e2 -- literal require call
-      and n.e1.kind == "variable" and n.e1.tk == "require"
+   if not (n.e1 and n.e2) then
+      return nil
+   end
+   if n.op and n.op.op == "." then
+      -- require("str").something
+      return node_is_require_call(n.e1)
+   elseif n.e1.kind == "variable" and n.e1.tk == "require"
       and n.e2.kind == "expression_list" and #n.e2 == 1
       and n.e2[1].kind == "string"
    then
+      -- require("str")
       return n.e2[1].conststr
-   elseif n.op and n.op.op == "@funcall" -- pcall(require, "str")
+   elseif n.op and n.op.op == "@funcall"
       and n.e1 and n.e1.tk == "pcall"
       and n.e2 and #n.e2 == 2
       and n.e2[1].kind == "variable" and n.e2[1].tk == "require"
       and n.e2[2].kind == "string" and n.e2[2].conststr
    then
+      -- pcall(require, "str")
       return n.e2[2].conststr
    else
       return nil -- table.insert cares about arity
@@ -4031,11 +4038,20 @@ parse_type_declaration = function(ps: ParseState, i: integer, node_name: NodeKin
 
    if ps.tokens[i].kind == "identifier" and ps.tokens[i].tk == "require" then
       local istart = i
-      i, asgn.value = parse_call_or_assignment(ps, i)
-      if asgn.value and not node_is_require_call(asgn.value) then
-         fail(ps, istart, "require() for type declarations must have a literal argument")
+      i, asgn.value = parse_expression(ps, i)
+      if asgn.value then
+         if asgn.value.op and asgn.value.op.op ~= "@funcall" and asgn.value.op.op ~= "." then
+            fail(ps, istart, "require() in type declarations cannot be part of larger expressions")
+            return i
+         end
+         if not node_is_require_call(asgn.value) then
+            fail(ps, istart, "require() for type declarations must have a literal argument")
+            return i
+         end
+         return i, asgn
+      else
+         return i
       end
-      return i, asgn
    end
 
    i, asgn.value = parse_newtype(ps, i)
@@ -10577,6 +10593,24 @@ do
          ty = (ty is TypeAliasType) and self:resolve_typealias(ty) or ty
          local td = (ty is TypeDeclType) and ty or a_type(value, "typedecl", { def = ty } as TypeDeclType)
          return td
+      elseif value.kind == "op"
+         and value.op.op == "."
+      then
+         local ty = self:get_typedecl(value.e1)
+         if ty is TypeDeclType then
+            local def = ty.def
+            if def is RecordType then
+               local t = def.fields[value.e2.tk]
+               if t then
+                  return a_type(value, "typedecl", { def = t } as TypeDeclType)
+               else
+                  return self.errs:invalid_at(value.e2, "type not found")
+               end
+            else
+               return self.errs:invalid_at(value.e2, "type is not a record")
+            end
+         end
+         return ty
       else
          local newtype = value.newtype
          if newtype is TypeAliasType then