Auto merge of #17821 - Veykril:project-model-cleanup, r=Veykril

internal: Remove unnecessary CfgFlag definition in project-model

Author: bors

crates/base-db/src/input.rs

@@ -690,6 +690,14 @@ impl Env {
     pub fn extend_from_other(&mut self, other: &Env) {
         self.entries.extend(other.entries.iter().map(|(x, y)| (x.to_owned(), y.to_owned())));
     }
+
+    pub fn is_empty(&self) -> bool {
+        self.entries.is_empty()
+    }
+
+    pub fn insert(&mut self, k: impl Into<String>, v: impl Into<String>) -> Option<String> {
+        self.entries.insert(k.into(), v.into())
+    }
 }
 
 impl From<Env> for Vec<(String, String)> {
@@ -700,6 +708,15 @@ impl From<Env> for Vec<(String, String)> {
     }
 }
 
+impl<'a> IntoIterator for &'a Env {
+    type Item = (&'a String, &'a String);
+    type IntoIter = std::collections::hash_map::Iter<'a, String, String>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.entries.iter()
+    }
+}
+
 #[derive(Debug)]
 pub struct CyclicDependenciesError {
     path: Vec<(CrateId, Option<CrateDisplayName>)>,

crates/cfg/src/lib.rs

@@ -108,6 +108,14 @@ impl<'a> IntoIterator for &'a CfgOptions {
     }
 }
 
+impl FromIterator<CfgAtom> for CfgOptions {
+    fn from_iter<T: IntoIterator<Item = CfgAtom>>(iter: T) -> Self {
+        let mut options = CfgOptions::default();
+        options.extend(iter);
+        options
+    }
+}
+
 #[derive(Default, Clone, Debug, PartialEq, Eq)]
 pub struct CfgDiff {
     // Invariants: No duplicates, no atom that's both in `enable` and `disable`.