[lukaszsamson]

Summary

ElixirSense.Core.SurroundContext.to_binding/2 crashed with a FunctionClauseError when the cursor was on a dotted identifier inside a struct literal, e.g. %nav.foo{}.

Code.Fragment.surround_context/2 reports the inner identifier as {:local_or_var, ~c"nav"}, but inside_dot_to_binding/2 only handled {:var, _}, so no clause matched.

This PR adds {:local_or_var, _} clauses that mirror the existing {:var, _} clauses, including the __MODULE__ special case.

Crash

** (FunctionClauseError) no function clause matching in ElixirSense.Core.SurroundContext.inside_dot_to_binding/2
  elixir_sense/core/surround_context.ex:97: ElixirSense.Core.SurroundContext.inside_dot_to_binding({:local_or_var, ~c"nav"}, nil)
  elixir_sense/core/surround_context.ex:35: ElixirSense.Core.SurroundContext.to_binding_impl/2
  elixir_sense/core/surround_context.ex:6: ElixirSense.Core.SurroundContext.to_binding/2
  language_server/providers/hover/docs.ex:112: ElixirLS.LanguageServer.Providers.Hover.Docs.all/3

Repro

mix run -e 'c = Code.Fragment.surround_context("%nav.foo{}", {1, 7}); IO.inspect ElixirSense.Core.SurroundContext.to_binding(c.context, nil)'

Before this change it raises; after it returns {{:variable, :nav, :any}, :foo}.

Other shapes checked

Probed every cursor column for %nav.foo{}, %nav.foo.bar{}, %mod.foo.bar{}, %foo.bar.baz{}, %x.y{a: 1}, %__MODULE__.foo{}, %__MODULE__.foo.bar{}, %@attr.foo{}, %@a.b.c{}, %Foo.bar{}, %Foo.Bar.baz{}, %Foo.bar().baz{}, %foo().bar{}, %(x).foo{}, %:erlang.foo{}. The only crashing inner shape was {:local_or_var, _}, which the new clauses cover. The other shapes already return a result.

Tests

New test/elixir_sense/core/surround_context_test.exs covers the repro, the other cursor columns, the nested and __MODULE__ variants, and the already-working @attr, alias, and call shapes. Against unmodified master, 9 of these tests fail.