Merge pull request #1655 from dtolnay/constparam

Apply const argument legalization to default value of ConstParam
dtolnay · May 15, 2024 · 9597ebc · 9597ebc
2 parents 1d218f9 + dde4a0f
commit 9597ebc
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Showing 2 changed files with 35 additions and 32 deletions.
diff --git a/src/generics.rs b/src/generics.rs
@@ -989,14 +989,16 @@ pub(crate) mod parsing {
 }
 
 #[cfg(feature = "printing")]
-mod printing {
+pub(crate) mod printing {
     use crate::attr::FilterAttrs;
+    use crate::expr::Expr;
     use crate::generics::{
         BoundLifetimes, ConstParam, GenericParam, Generics, ImplGenerics, LifetimeParam,
         PredicateLifetime, PredicateType, TraitBound, TraitBoundModifier, Turbofish, TypeGenerics,
         TypeParam, WhereClause,
     };
     use crate::print::TokensOrDefault;
+    use crate::token;
     use proc_macro2::TokenStream;
     use quote::{ToTokens, TokenStreamExt};
 
@@ -1214,7 +1216,7 @@ mod printing {
             self.ty.to_tokens(tokens);
             if let Some(default) = &self.default {
                 TokensOrDefault(&self.eq_token).to_tokens(tokens);
-                default.to_tokens(tokens);
+                print_const_argument(default, tokens);
             }
         }
     }
@@ -1247,4 +1249,30 @@ mod printing {
             self.bounds.to_tokens(tokens);
         }
     }
+
+    pub(crate) fn print_const_argument(expr: &Expr, tokens: &mut TokenStream) {
+        match expr {
+            Expr::Lit(expr) => expr.to_tokens(tokens),
+
+            Expr::Path(expr)
+                if expr.attrs.is_empty()
+                    && expr.qself.is_none()
+                    && expr.path.get_ident().is_some() =>
+            {
+                expr.to_tokens(tokens);
+            }
+
+            #[cfg(feature = "full")]
+            Expr::Block(expr) => expr.to_tokens(tokens),
+
+            #[cfg(not(feature = "full"))]
+            Expr::Verbatim(expr) => expr.to_tokens(tokens),
+
+            // ERROR CORRECTION: Add braces to make sure that the
+            // generated code is valid.
+            _ => token::Brace::default().surround(tokens, |tokens| {
+                expr.to_tokens(tokens);
+            }),
+        }
+    }
 }
diff --git a/src/path.rs b/src/path.rs
@@ -688,15 +688,14 @@ pub(crate) mod parsing {
 
 #[cfg(feature = "printing")]
 pub(crate) mod printing {
-    use crate::expr::Expr;
+    use crate::generics;
     use crate::path::{
         AngleBracketedGenericArguments, AssocConst, AssocType, Constraint, GenericArgument,
         ParenthesizedGenericArguments, Path, PathArguments, PathSegment, QSelf,
     };
     use crate::print::TokensOrDefault;
     #[cfg(feature = "parsing")]
     use crate::spanned::Spanned;
-    use crate::token;
     #[cfg(feature = "parsing")]
     use proc_macro2::Span;
     use proc_macro2::TokenStream;
@@ -741,40 +740,16 @@ pub(crate) mod printing {
             match self {
                 GenericArgument::Lifetime(lt) => lt.to_tokens(tokens),
                 GenericArgument::Type(ty) => ty.to_tokens(tokens),
-                GenericArgument::Const(expr) => print_const_argument(expr, tokens),
+                GenericArgument::Const(expr) => {
+                    generics::printing::print_const_argument(expr, tokens);
+                }
                 GenericArgument::AssocType(assoc) => assoc.to_tokens(tokens),
                 GenericArgument::AssocConst(assoc) => assoc.to_tokens(tokens),
                 GenericArgument::Constraint(constraint) => constraint.to_tokens(tokens),
             }
         }
     }
 
-    fn print_const_argument(expr: &Expr, tokens: &mut TokenStream) {
-        match expr {
-            Expr::Lit(expr) => expr.to_tokens(tokens),
-
-            Expr::Path(expr)
-                if expr.attrs.is_empty()
-                    && expr.qself.is_none()
-                    && expr.path.get_ident().is_some() =>
-            {
-                expr.to_tokens(tokens);
-            }
-
-            #[cfg(feature = "full")]
-            Expr::Block(expr) => expr.to_tokens(tokens),
-
-            #[cfg(not(feature = "full"))]
-            Expr::Verbatim(expr) => expr.to_tokens(tokens),
-
-            // ERROR CORRECTION: Add braces to make sure that the
-            // generated code is valid.
-            _ => token::Brace::default().surround(tokens, |tokens| {
-                expr.to_tokens(tokens);
-            }),
-        }
-    }
-
     #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
     impl ToTokens for AngleBracketedGenericArguments {
         fn to_tokens(&self, tokens: &mut TokenStream) {
@@ -834,7 +809,7 @@ pub(crate) mod printing {
             self.ident.to_tokens(tokens);
             self.generics.to_tokens(tokens);
             self.eq_token.to_tokens(tokens);
-            print_const_argument(&self.value, tokens);
+            generics::printing::print_const_argument(&self.value, tokens);
         }
     }