codegen: Omit version constraints on imports if scope already guards it

This removes unnecessary (duplicate) `#[cfg]` attributes on `use`
imports where the surrounding `mod` (when in a file that fully defines a
`struct`) already declares this constraint.  This does not suffice for
`flags`/`enums` where multiple types live in a single shared file
without surrounding constraint.  When the feature requirement is already
described it is superfluous (and noisy) to specify it again.

src/codegen/constants.rs

@@ -21,7 +21,7 @@ pub fn generate(env: &Env, root_path: &Path, mod_rs: &mut Vec<String>) {
 
     file_saver::save_to_file(path, env.config.make_backup, |w| {
         general::start_comments(w, &env.config)?;
-        general::uses(w, env, &imports)?;
+        general::uses(w, env, &imports, None)?;
         writeln!(w)?;
 
         mod_rs.push("\nmod constants;".into());

src/codegen/enums.rs

@@ -28,7 +28,7 @@ pub fn generate(env: &Env, root_path: &Path, mod_rs: &mut Vec<String>) {
     let path = root_path.join("enums.rs");
     file_saver::save_to_file(path, env.config.make_backup, |w| {
         general::start_comments(w, &env.config)?;
-        general::uses(w, env, &env.analysis.enum_imports)?;
+        general::uses(w, env, &env.analysis.enum_imports, None)?;
         writeln!(w)?;
 
         mod_rs.push("\nmod enums;".into());

src/codegen/flags.rs

@@ -25,7 +25,7 @@ pub fn generate(env: &Env, root_path: &Path, mod_rs: &mut Vec<String>) {
     let path = root_path.join("flags.rs");
     file_saver::save_to_file(path, env.config.make_backup, |w| {
         general::start_comments(w, &env.config)?;
-        general::uses(w, env, &env.analysis.flags_imports)?;
+        general::uses(w, env, &env.analysis.flags_imports, None)?;
         writeln!(w)?;
 
         mod_rs.push("\nmod flags;".into());

src/codegen/functions.rs

@@ -17,7 +17,7 @@ pub fn generate(env: &Env, root_path: &Path, mod_rs: &mut Vec<String>) {
     let path = root_path.join("functions.rs");
     file_saver::save_to_file(path, env.config.make_backup, |w| {
         general::start_comments(w, &env.config)?;
-        general::uses(w, env, &functions.imports)?;
+        general::uses(w, env, &functions.imports, None)?;
 
         writeln!(w)?;
 

src/codegen/general.rs

@@ -65,7 +65,12 @@ pub fn single_version_file(w: &mut dyn Write, conf: &Config, prefix: &str) -> Re
     )
 }
 
-pub fn uses(w: &mut dyn Write, env: &Env, imports: &Imports) -> Result<()> {
+pub fn uses(
+    w: &mut dyn Write,
+    env: &Env,
+    imports: &Imports,
+    outer_version: Option<Version>,
+) -> Result<()> {
     writeln!(w)?;
     for (name, ref scope) in imports.iter() {
         if !scope.constraints.is_empty() {
@@ -80,8 +85,9 @@ pub fn uses(w: &mut dyn Write, env: &Env, imports: &Imports) -> Result<()> {
                 scope.constraints.join(", ")
             )?;
         }
+        let version = Version::if_stricter_than(scope.version, outer_version);
 
-        version_condition(w, env, scope.version, false, 0)?;
+        version_condition(w, env, version, false, 0)?;
         writeln!(w, "use {};", name)?;
     }
 

src/codegen/object.rs

@@ -20,7 +20,7 @@ pub fn generate(
     generate_display_trait: bool,
 ) -> Result<()> {
     general::start_comments(w, &env.config)?;
-    general::uses(w, env, &analysis.imports)?;
+    general::uses(w, env, &analysis.imports, analysis.version)?;
 
     general::define_object_type(
         w,

src/codegen/record.rs

@@ -10,7 +10,7 @@ pub fn generate(w: &mut dyn Write, env: &Env, analysis: &analysis::record::Info)
     let type_ = analysis.type_(&env.library);
 
     general::start_comments(w, &env.config)?;
-    general::uses(w, env, &analysis.imports)?;
+    general::uses(w, env, &analysis.imports, type_.version)?;
 
     if analysis.is_boxed {
         if let Some((ref glib_get_type, _)) = analysis.glib_get_type {