Process fields even when structs are unknown, closes #15156

Author: josevalim

lib/elixir/lib/module/types/expr.ex

@@ -243,6 +243,12 @@ defmodule Module.Types.Expr do
         end
       end)
     else
+      context =
+        Enum.reduce(pairs, context, fn {_key, value}, context ->
+          {_type, context} = of_expr(value, term(), expr, stack, context)
+          context
+        end)
+
       {error_type(), context}
     end
   end

lib/elixir/lib/module/types/pattern.ex

@@ -751,6 +751,12 @@ defmodule Module.Types.Pattern do
         {{:closed_map, static, dynamic}, precise?, context}
       end
     else
+      context =
+        Enum.reduce(args, context, fn {key, value}, context ->
+          {_, _, context} = of_pattern(value, [{:key, key} | path], stack, context)
+          context
+        end)
+
       {error_type(), false, context}
     end
   end

lib/elixir/test/elixir/module/types/expr_test.exs

@@ -1253,6 +1253,17 @@ defmodule Module.Types.ExprTest do
                "struct Enumerable is undefined (there is such module but it does not define a struct)"
     end
 
+    test "updating field in unknown struct" do
+      assert typeerror!(
+               [x],
+               (
+                 %UNKNOWN.URI{x | foo: y = 123}
+                 y
+               )
+             ) =~
+               "struct UNKNOWN.URI is undefined (module UNKNOWN.URI is not available or is yet to be defined)"
+    end
+
     test "updating unknown field" do
       {_, [diagnostic]} = typediag!([%URI{} = x], %URI{x | unknown: 123})
       assert diagnostic.severity == :warning

lib/elixir/test/elixir/module/types/pattern_test.exs

@@ -193,6 +193,11 @@ defmodule Module.Types.PatternTest do
                "struct Enumerable is undefined (there is such module but it does not define a struct)"
     end
 
+    test "fields access on unknown struct" do
+      assert typeerror!([%UNKNOWN.URI{reason: reason}], reason) =~
+               "struct UNKNOWN.URI is undefined (module UNKNOWN.URI is not available or is yet to be defined)"
+    end
+
     test "unknown field" do
       {_, [diagnostic]} = typediag!([%URI{unknown: _} = x], x)
       assert diagnostic.severity == :error