diff --git a/mesonbuild/coredata.py b/mesonbuild/coredata.py
index 4c93ffb28..7f622e582 100644
--- a/mesonbuild/coredata.py
+++ b/mesonbuild/coredata.py
@@ -351,6 +351,37 @@ class CoreData:
     def get_external_preprocess_args(self, lang):
         return self.external_preprocess_args[lang]
 
+    def merge_user_options(self, options):
+        for (name, value) in options.items():
+            if name not in self.user_options:
+                self.user_options[name] = value
+            else:
+                oldval = self.user_options[name]
+                if type(oldval) != type(value):
+                    self.user_options[name] = value
+
+    def set_options(self, options):
+        for o in options:
+            if '=' not in o:
+                raise MesonException('Value "%s" not of type "a=b".' % o)
+            (k, v) = o.split('=', 1)
+            if is_builtin_option(k):
+                self.set_builtin_option(k, v)
+            elif k in self.backend_options:
+                tgt = self.backend_options[k]
+                tgt.set_value(v)
+            elif k in self.user_options:
+                tgt = self.user_options[k]
+                tgt.set_value(v)
+            elif k in self.compiler_options:
+                tgt = self.compiler_options[k]
+                tgt.set_value(v)
+            elif k in self.base_options:
+                tgt = self.base_options[k]
+                tgt.set_value(v)
+            else:
+                raise MesonException('Unknown option %s.' % k)
+
 def load(build_dir):
     filename = os.path.join(build_dir, 'meson-private', 'coredata.dat')
     load_fail_msg = 'Coredata file {!r} is corrupted. Try with a fresh build tree.'.format(filename)
diff --git a/mesonbuild/environment.py b/mesonbuild/environment.py
index fb1e07088..a859bad4b 100644
--- a/mesonbuild/environment.py
+++ b/mesonbuild/environment.py
@@ -386,15 +386,6 @@ class Environment:
             previous_is_plaind = i == '-D'
         return False
 
-    def merge_options(self, options):
-        for (name, value) in options.items():
-            if name not in self.coredata.user_options:
-                self.coredata.user_options[name] = value
-            else:
-                oldval = self.coredata.user_options[name]
-                if type(oldval) != type(value):
-                    self.coredata.user_options[name] = value
-
     @staticmethod
     def get_gnu_compiler_defines(compiler):
         """
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index c51382330..320e54396 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -2306,7 +2306,7 @@ to directly access options of other subprojects.''')
                                                   self.build.environment.cmd_line_options.projectoptions,
                                                   )
             oi.process(self.option_file)
-            self.build.environment.merge_options(oi.options)
+            self.coredata.merge_user_options(oi.options)
         self.set_backend()
         self.active_projectname = proj_name
         self.project_version = kwargs.get('version', 'undefined')
diff --git a/mesonbuild/mconf.py b/mesonbuild/mconf.py
index abaf0af10..0b33ba326 100644
--- a/mesonbuild/mconf.py
+++ b/mesonbuild/mconf.py
@@ -42,6 +42,9 @@ class Conf:
     def clear_cache(self):
         self.coredata.deps = {}
 
+    def set_options(self, options):
+        self.coredata.set_options(options)
+
     def save(self):
         # Only called if something has changed so overwrite unconditionally.
         coredata.save(self.coredata, self.build_dir)
@@ -94,28 +97,6 @@ class Conf:
             else:
                 print('  {0:{width[0]}} {1:{width[1]}} {3:{width[3]}}'.format(*line, width=col_widths))
 
-    def set_options(self, options):
-        for o in options:
-            if '=' not in o:
-                raise ConfException('Value "%s" not of type "a=b".' % o)
-            (k, v) = o.split('=', 1)
-            if coredata.is_builtin_option(k):
-                self.coredata.set_builtin_option(k, v)
-            elif k in self.coredata.backend_options:
-                tgt = self.coredata.backend_options[k]
-                tgt.set_value(v)
-            elif k in self.coredata.user_options:
-                tgt = self.coredata.user_options[k]
-                tgt.set_value(v)
-            elif k in self.coredata.compiler_options:
-                tgt = self.coredata.compiler_options[k]
-                tgt.set_value(v)
-            elif k in self.coredata.base_options:
-                tgt = self.coredata.base_options[k]
-                tgt.set_value(v)
-            else:
-                raise ConfException('Unknown option %s.' % k)
-
     def print_conf(self):
         print('Core properties:')
         print('  Source dir', self.build.environment.source_dir)