From ec82a79ebe77c6d0ad1da31a595593fce0b6a496 Mon Sep 17 00:00:00 2001
From: overlookmotel <557937+overlookmotel@users.noreply.github.com>
Date: Fri, 9 Aug 2024 10:52:21 +0000
Subject: [PATCH] refactor(ast_codegen): trim `r#` from start of field names
 (#4785)

Some struct fields are reserved names e.g. `type`. They are written in source as `r#type`. Trim off the `r#` prefix in `FieldDef::name` and add it back when generating output.

Main motivation is to have the unescaped field names in JSON schema.
---
 .../src/generators/assert_layouts.rs          |  5 +++--
 tasks/ast_codegen/src/schema/mod.rs           |  5 ++++-
 tasks/ast_codegen/src/util.rs                 | 22 ++++++++++++++++++-
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/tasks/ast_codegen/src/generators/assert_layouts.rs b/tasks/ast_codegen/src/generators/assert_layouts.rs
index d6ee9e6fa6d7d..937aadde25136 100644
--- a/tasks/ast_codegen/src/generators/assert_layouts.rs
+++ b/tasks/ast_codegen/src/generators/assert_layouts.rs
@@ -1,11 +1,12 @@
 use proc_macro2::TokenStream;
-use quote::{format_ident, quote};
+use quote::quote;
 use syn::Type;
 
 use crate::{
     codegen::LateCtx,
     output,
     schema::{FieldDef, ToType, TypeDef},
+    util::ToIdent,
     Generator, GeneratorOutput,
 };
 
@@ -96,7 +97,7 @@ fn with_offsets_assertion(
 
     let assertions = fields.iter().zip(offsets).filter(|(field, _)| field.vis.is_pub()).map(
         |(field, offset)| {
-            let field = field.name.as_ref().map(|it| format_ident!("{it}"));
+            let field = field.name.as_ref().map(ToIdent::to_ident);
             quote! {
                 assert!(offset_of!(#ty, #field) == #offset);
             }
diff --git a/tasks/ast_codegen/src/schema/mod.rs b/tasks/ast_codegen/src/schema/mod.rs
index 8b6406112443f..74d1dea0a988f 100644
--- a/tasks/ast_codegen/src/schema/mod.rs
+++ b/tasks/ast_codegen/src/schema/mod.rs
@@ -238,7 +238,10 @@ fn lower_inherit(inherit: &rust::Inherit, ctx: &codegen::EarlyCtx) -> InheritDef
 
 fn lower_field(field: &syn::Field, ctx: &codegen::EarlyCtx) -> FieldDef {
     FieldDef {
-        name: field.ident.as_ref().map(ToString::to_string),
+        name: field
+            .ident
+            .as_ref()
+            .map(|ident| ident.to_string().trim_start_matches("r#").to_string()),
         vis: Visibility::from(&field.vis),
         typ: create_type_ref(&field.ty, ctx),
         markers: parse_inner_markers(&field.attrs).unwrap(),
diff --git a/tasks/ast_codegen/src/util.rs b/tasks/ast_codegen/src/util.rs
index 0610ea72e02c8..52e48353e9fc8 100644
--- a/tasks/ast_codegen/src/util.rs
+++ b/tasks/ast_codegen/src/util.rs
@@ -282,12 +282,32 @@ impl TokenStreamExt for TokenStream {
     }
 }
 
+// From https://doc.rust-lang.org/reference/keywords.html
+#[rustfmt::skip]
+static RESERVED_NAMES: &[&str] = &[
+    // Strict keywords
+    "as", "break", "const", "continue", "crate", "else", "enum", "extern", "false", "fn", "for", "if",
+    "impl", "in", "let", "loop", "match", "mod", "move", "mut", "pub", "ref", "return", "self", "Self",
+    "static", "struct", "super", "trait", "true", "type", "unsafe", "use", "where", "while", "async",
+    "await", "dyn",
+    // Reserved keywords
+    "abstract", "become", "box", "do", "final", "macro", "override", "priv", "typeof", "unsized",
+    "virtual", "yield", "try",
+    // Weak keywords
+    "macro_rules", "union", // "dyn" also listed as a weak keyword, but is already on strict list
+];
+
 impl<S> ToIdent for S
 where
     S: AsRef<str>,
 {
     fn to_ident(&self) -> Ident {
-        format_ident!("{}", self.as_ref())
+        let name = self.as_ref();
+        if RESERVED_NAMES.contains(&name) {
+            format_ident!("r#{name}")
+        } else {
+            format_ident!("{name}")
+        }
     }
 }