fix(lsp): Prevent lsp crash when module cannot be found (#2003)

compiler/src/language_server/hover.re

@@ -126,11 +126,17 @@ let declaration_lens = (ident: Ident.t, decl: Types.type_declaration) => {
 };
 
 let include_lens = (env: Env.t, path: Path.t) => {
-  let module_decl = Env.find_module(path, None, env);
-  markdown_join(
-    grain_code_block("module " ++ Path.name(path)),
-    module_lens(module_decl),
-  );
+  let header = grain_code_block("module " ++ Path.name(path));
+  let decl = Env.find_module(path, None, env);
+  let module_decl =
+    switch (Modules.get_provides(decl)) {
+    | [_, ..._] => Some(module_lens(decl))
+    | [] => None
+    };
+  switch (module_decl) {
+  | Some(mod_sig) => markdown_join(header, mod_sig)
+  | None => header
+  };
 };
 
 let exception_declaration_lens =
@@ -184,12 +190,16 @@ let process =
       )
     | [Module({decl, loc}), ..._] =>
       send_hover(~id, ~range=Utils.loc_to_range(loc), module_lens(decl))
-    | [Include({env, path, loc}), ..._] =>
-      send_hover(
-        ~id,
-        ~range=Utils.loc_to_range(loc),
-        include_lens(env, path),
-      )
+    | [Include({path, loc}), ..._] =>
+      let hover_lens =
+        try(Some(include_lens(program.env, path))) {
+        | Not_found => None
+        };
+      switch (hover_lens) {
+      | Some(lens) => send_hover(~id, ~range=Utils.loc_to_range(loc), lens)
+      | None => send_no_result(~id)
+      };
+
     | _ => send_no_result(~id)
     };
   };

compiler/src/language_server/sourcetree.re

@@ -170,7 +170,6 @@ module type Sourcetree = {
         definition: option(Location.t),
       })
     | Include({
-        env: Env.t,
         path: Path.t,
         loc: Location.t,
       });
@@ -260,7 +259,6 @@ module Sourcetree: Sourcetree = {
         definition: option(Location.t),
       })
     | Include({
-        env: Env.t,
         path: Path.t,
         loc: Location.t,
       });
@@ -534,11 +532,7 @@ module Sourcetree: Sourcetree = {
               [
                 (
                   loc_to_interval(stmt.ttop_loc),
-                  Include({
-                    env: stmt.ttop_env,
-                    path: inc.tinc_path,
-                    loc: stmt.ttop_loc,
-                  }),
+                  Include({path: inc.tinc_path, loc: stmt.ttop_loc}),
                 ),
                 ...segments^,
               ]