fix(*): gcc 7 weird uninitialized warnings

I think most of them are incorrect.
I didn't find a workaround for the one at json.hpp.
So, I just disabled this warning at server.cpp

src/api/module.cpp

@@ -24,7 +24,8 @@ lean_bool lean_env_import(lean_env env, lean_ios ios, lean_list_name modules, le
     auto new_env = to_env_ref(env);
     std::vector<module_name> imports;
     for (name const & n : to_list_name_ref(modules)) {
-        imports.push_back({n, optional<unsigned>()});
+        module_name m(n);
+        imports.push_back(m);
     }
     new_env = import_modules(new_env, "", imports, mk_olean_loader(standard_search_path().get_path()));
     *r = of_env(new environment(new_env));

src/frontends/lean/parser.cpp

@@ -2337,31 +2337,35 @@ void parser::parse_imports(unsigned & fingerprint, std::vector<module_name> & im
         prelude = true;
     }
     if (!prelude) {
-        imports.push_back({ "init", optional<unsigned>() });
+        module_name m("init");
+        imports.push_back(m);
     }
     while (curr_is_token(get_import_tk())) {
         m_last_cmd_pos = pos();
         next();
         while (true) {
-            pos_info p = pos();
-            optional<unsigned> k;
+            pos_info p  = pos();
+            bool k_init = false;
+            unsigned k  = 0;
             try {
                 unsigned h = 0;
                 while (true) {
                     if (curr_is_token(get_period_tk())) {
-                        if (!k) {
+                        if (!k_init) {
                             k = 0;
+                            k_init = true;
                         } else {
-                            k = *k + 1;
+                            k = k + 1;
                             h++;
                         }
                         next();
                     } else if (curr_is_token(get_ellipsis_tk())) {
-                        if (!k) {
+                        if (!k_init) {
                             k = 2;
+                            k_init = true;
                             h = 2;
                         } else {
-                            k = *k + 3;
+                            k = k + 3;
                             h += 3;
                         }
                         next();
@@ -2374,14 +2378,20 @@ void parser::parse_imports(unsigned & fingerprint, std::vector<module_name> & im
                     break;
                 name f = get_name_val();
                 fingerprint = hash(fingerprint, f.hash());
-                if (k) {
+                if (k_init) {
                     fingerprint = hash(fingerprint, h);
                 }
-                imports.push_back({f, k});
+                if (k_init) {
+                    module_name m(f, k);
+                    imports.push_back(m);
+                } else {
+                    module_name m(f);
+                    imports.push_back(m);
+                }
                 next();
             } catch (break_at_pos_exception & e) {
-                if (k)
-                    e.m_token_info.m_token = std::string(*k + 1, '.') + e.m_token_info.m_token.to_string();
+                if (k_init)
+                    e.m_token_info.m_token = std::string(k + 1, '.') + e.m_token_info.m_token.to_string();
                 e.m_token_info.m_context = break_at_pos_exception::token_context::import;
                 e.m_token_info.m_pos = p;
                 throw;

src/frontends/smt2/parser.cpp

@@ -700,8 +700,8 @@ public:
         scoped_expr_caching disable(false);
 
         auto mod_ldr = mk_olean_loader(m_path);
-        optional<unsigned> k;
-        m_env = import_modules(m_env, get_stream_name(), {{"init", k}, {"smt", k}}, mod_ldr);
+        m_env = import_modules(m_env, get_stream_name(), {module_name("init"), module_name("smt")},
+                               mod_ldr);
 
         bool ok = true;
         try {

src/library/module.h

@@ -25,6 +25,9 @@ public:
 struct module_name {
     name               m_name;
     optional<unsigned> m_relative;
+    module_name() {}
+    module_name(name const & n, unsigned k):m_name(n), m_relative(k) {}
+    explicit module_name(name const & n):m_name(n) {}
 };
 
 struct modification;

src/shell/server.cpp

@@ -5,6 +5,12 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Gabriel Ebner, Leonardo de Moura, Sebastian Ullrich
 */
 #if defined(LEAN_JSON)
+// Remark: gcc 7 produces a warning at json.hpp
+// We believe it is a spurious warning
+#if defined(__GNUC__) && !defined(__CLANG__)
+#pragma GCC diagnostic ignored "-Wuninitialized"
+#endif
+
 #include <list>
 #include <string>
 #include <vector>
@@ -26,7 +32,6 @@ Authors: Gabriel Ebner, Leonardo de Moura, Sebastian Ullrich
 #include "shell/server.h"
 
 namespace lean {
-
 struct all_messages_msg {
     std::vector<message> m_msgs;
 

src/util/optional.h

@@ -29,7 +29,7 @@ public:
             new (&m_value) T(other.m_value);
     }
     optional(optional && other):m_some(other.m_some) {
-        if (m_some)
+        if (other.m_some)
             new (&m_value) T(std::forward<T>(other.m_value));
     }
     explicit optional(T const & v):m_some(true) {