From ceaec9d8666614f6e84506b84f4b740538cb6d50 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Sat, 20 Nov 2021 16:17:16 +0100
Subject: [PATCH] internal: Replace Vec with Box in hir Pat

---
 crates/hir_def/src/body/lower.rs |  6 +--
 crates/hir_def/src/expr.rs       | 66 +++++++++++++-------------------
 crates/hir_ty/src/infer/pat.rs   |  8 ++--
 3 files changed, 33 insertions(+), 47 deletions(-)

diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index 48aa1b3464b..e322a953844 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -813,7 +813,7 @@ impl ExprCollector<'_> {
             ast::Pat::RecordPat(p) => {
                 let path =
                     p.path().and_then(|path| self.expander.parse_path(self.db, path)).map(Box::new);
-                let args: Vec<_> = p
+                let args = p
                     .record_pat_field_list()
                     .expect("every struct should have a field list")
                     .fields()
@@ -903,7 +903,7 @@ impl ExprCollector<'_> {
         }
     }
 
-    fn collect_tuple_pat(&mut self, args: AstChildren<ast::Pat>) -> (Vec<PatId>, Option<usize>) {
+    fn collect_tuple_pat(&mut self, args: AstChildren<ast::Pat>) -> (Box<[PatId]>, Option<usize>) {
         // Find the location of the `..`, if there is one. Note that we do not
         // consider the possibility of there being multiple `..` here.
         let ellipsis = args.clone().position(|p| matches!(p, ast::Pat::RestPat(_)));
@@ -962,7 +962,7 @@ impl From<ast::LiteralKind> for Literal {
                 Literal::Float(Default::default(), ty)
             }
             LiteralKind::ByteString(bs) => {
-                let text = bs.value().map(Vec::from).unwrap_or_else(Default::default);
+                let text = bs.value().map(Box::from).unwrap_or_else(Default::default);
                 Literal::ByteString(text)
             }
             LiteralKind::String(_) => Literal::String(Default::default()),
diff --git a/crates/hir_def/src/expr.rs b/crates/hir_def/src/expr.rs
index 587a5ce46d4..e6518c3e2d7 100644
--- a/crates/hir_def/src/expr.rs
+++ b/crates/hir_def/src/expr.rs
@@ -41,7 +41,7 @@ pub type LabelId = Idx<Label>;
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum Literal {
     String(String),
-    ByteString(Vec<u8>),
+    ByteString(Box<[u8]>),
     Char(char),
     Bool(bool),
     Int(i128, Option<BuiltinInt>),
@@ -182,7 +182,7 @@ pub enum Expr {
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum Array {
-    ElementList(Vec<ExprId>),
+    ElementList(Box<[ExprId]>),
     Repeat { initializer: ExprId, repeat: ExprId },
 }
 
@@ -228,23 +228,23 @@ impl Expr {
             Expr::If { condition, then_branch, else_branch } => {
                 f(*condition);
                 f(*then_branch);
-                if let Some(else_branch) = else_branch {
-                    f(*else_branch);
+                if let &Some(else_branch) = else_branch {
+                    f(else_branch);
                 }
             }
             Expr::Block { statements, tail, .. } => {
                 for stmt in statements.iter() {
                     match stmt {
                         Statement::Let { initializer, .. } => {
-                            if let Some(expr) = initializer {
-                                f(*expr);
+                            if let &Some(expr) = initializer {
+                                f(expr);
                             }
                         }
                         Statement::Expr { expr: expression, .. } => f(*expression),
                     }
                 }
-                if let Some(expr) = tail {
-                    f(*expr);
+                if let &Some(expr) = tail {
+                    f(expr);
                 }
             }
             Expr::TryBlock { body }
@@ -262,34 +262,28 @@ impl Expr {
             }
             Expr::Call { callee, args } => {
                 f(*callee);
-                for arg in args.iter() {
-                    f(*arg);
-                }
+                args.iter().copied().for_each(f);
             }
             Expr::MethodCall { receiver, args, .. } => {
                 f(*receiver);
-                for arg in args.iter() {
-                    f(*arg);
-                }
+                args.iter().copied().for_each(f);
             }
             Expr::Match { expr, arms } => {
                 f(*expr);
-                for arm in arms.iter() {
-                    f(arm.expr);
-                }
+                arms.iter().map(|arm| arm.expr).for_each(f);
             }
             Expr::Continue { .. } => {}
             Expr::Break { expr, .. } | Expr::Return { expr } | Expr::Yield { expr } => {
-                if let Some(expr) = expr {
-                    f(*expr);
+                if let &Some(expr) = expr {
+                    f(expr);
                 }
             }
             Expr::RecordLit { fields, spread, .. } => {
                 for field in fields.iter() {
                     f(field.expr);
                 }
-                if let Some(expr) = spread {
-                    f(*expr);
+                if let &Some(expr) = spread {
+                    f(expr);
                 }
             }
             Expr::Lambda { body, .. } => {
@@ -300,11 +294,11 @@ impl Expr {
                 f(*rhs);
             }
             Expr::Range { lhs, rhs, .. } => {
-                if let Some(lhs) = rhs {
-                    f(*lhs);
+                if let &Some(lhs) = rhs {
+                    f(lhs);
                 }
-                if let Some(rhs) = lhs {
-                    f(*rhs);
+                if let &Some(rhs) = lhs {
+                    f(rhs);
                 }
             }
             Expr::Index { base, index } => {
@@ -320,17 +314,9 @@ impl Expr {
             | Expr::Box { expr } => {
                 f(*expr);
             }
-            Expr::Tuple { exprs } => {
-                for expr in exprs.iter() {
-                    f(*expr);
-                }
-            }
+            Expr::Tuple { exprs } => exprs.iter().copied().for_each(f),
             Expr::Array(a) => match a {
-                Array::ElementList(exprs) => {
-                    for expr in exprs {
-                        f(*expr);
-                    }
-                }
+                Array::ElementList(exprs) => exprs.iter().copied().for_each(f),
                 Array::Repeat { initializer, repeat } => {
                     f(*initializer);
                     f(*repeat)
@@ -386,15 +372,15 @@ pub struct RecordFieldPat {
 pub enum Pat {
     Missing,
     Wild,
-    Tuple { args: Vec<PatId>, ellipsis: Option<usize> },
-    Or(Vec<PatId>),
-    Record { path: Option<Box<Path>>, args: Vec<RecordFieldPat>, ellipsis: bool },
+    Tuple { args: Box<[PatId]>, ellipsis: Option<usize> },
+    Or(Box<[PatId]>),
+    Record { path: Option<Box<Path>>, args: Box<[RecordFieldPat]>, ellipsis: bool },
     Range { start: ExprId, end: ExprId },
-    Slice { prefix: Vec<PatId>, slice: Option<PatId>, suffix: Vec<PatId> },
+    Slice { prefix: Box<[PatId]>, slice: Option<PatId>, suffix: Box<[PatId]> },
     Path(Box<Path>),
     Lit(ExprId),
     Bind { mode: BindingAnnotation, name: Name, subpat: Option<PatId> },
-    TupleStruct { path: Option<Box<Path>>, args: Vec<PatId>, ellipsis: Option<usize> },
+    TupleStruct { path: Option<Box<Path>>, args: Box<[PatId]>, ellipsis: Option<usize> },
     Ref { pat: PatId, mutability: Mutability },
     Box { inner: PatId },
     ConstBlock(ExprId),
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index 9aaf7db87be..cc919327457 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -226,8 +226,8 @@ impl<'a> InferenceContext<'a> {
                     _ => self.err_ty(),
                 };
 
-                for pat_id in prefix.iter().chain(suffix) {
-                    self.infer_pat(*pat_id, &elem_ty, default_bm);
+                for &pat_id in prefix.iter().chain(suffix.iter()) {
+                    self.infer_pat(pat_id, &elem_ty, default_bm);
                 }
 
                 let pat_ty = match expected.kind(&Interner) {
@@ -235,8 +235,8 @@ impl<'a> InferenceContext<'a> {
                     _ => TyKind::Slice(elem_ty),
                 }
                 .intern(&Interner);
-                if let Some(slice_pat_id) = slice {
-                    self.infer_pat(*slice_pat_id, &pat_ty, default_bm);
+                if let &Some(slice_pat_id) = slice {
+                    self.infer_pat(slice_pat_id, &pat_ty, default_bm);
                 }
 
                 pat_ty