Remove TryFrom<proc_macro::Literal> impl for BoolLit

It does not make sense and would always fail.
LukasKalbertodt · May 28, 2021 · 966f6cc · 966f6cc
1 parent e7d7b4b
commit 966f6cc
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Showing 3 changed files with 45 additions and 36 deletions.
diff --git a/src/impls.rs b/src/impls.rs
@@ -138,7 +138,12 @@ macro_rules! impl_for_specific_lit {
             type Error = InvalidToken;
             fn try_from(tt: $($prefix)* TokenTree) -> Result<Self, Self::Error> {
                 let span = tt.span();
-                let res = impl_for_specific_lit!(@token_match [$($prefix)*] $variant tt);
+                let res = match tt {
+                    $($prefix)* TokenTree::Group(_) => Err(TokenKind::Group),
+                    $($prefix)* TokenTree::Punct(_) => Err(TokenKind::Punct),
+                    $($prefix)* TokenTree::Ident(_) => Err(TokenKind::Ident),
+                    $($prefix)* TokenTree::Literal(ref lit) => Ok(lit),
+                };
 
                 match res {
                     Ok(lit) => <$ty>::try_from(lit),
@@ -151,38 +156,44 @@ macro_rules! impl_for_specific_lit {
             }
         }
     };
-
-    // In case we are implementing it for `BoolLit`, we need to check for two extra cases.
-    (@token_match [$($prefix:tt)*] Bool $tt:ident) => {
-        match $tt {
-            $($prefix)* TokenTree::Group(_) => Err(TokenKind::Group),
-            $($prefix)* TokenTree::Punct(_) => Err(TokenKind::Punct),
-            $($prefix)* TokenTree::Ident(ref ident) if ident.to_string() == "true"
-                => return Ok(crate::BoolLit::True),
-            $($prefix)* TokenTree::Ident(ref ident) if ident.to_string() == "false"
-                => return Ok(crate::BoolLit::False),
-            $($prefix)* TokenTree::Ident(_) => Err(TokenKind::Ident),
-            $($prefix)* TokenTree::Literal(ref lit) => Ok(lit),
-        }
-    };
-    (@token_match [$($prefix:tt)*] $other:ident $tt:ident) => {
-        match $tt {
-            $($prefix)* TokenTree::Group(_) => Err(TokenKind::Group),
-            $($prefix)* TokenTree::Punct(_) => Err(TokenKind::Punct),
-            $($prefix)* TokenTree::Ident(_) => Err(TokenKind::Ident),
-            $($prefix)* TokenTree::Literal(ref lit) => Ok(lit),
-        }
-    };
 }
 
-helper!(impl_for_specific_lit, crate::BoolLit, Bool, BoolLit);
 helper!(impl_for_specific_lit, crate::IntegerLit<String>, Integer, IntegerLit);
 helper!(impl_for_specific_lit, crate::FloatLit<String>, Float, FloatLit);
 helper!(impl_for_specific_lit, crate::CharLit<String>, Char, CharLit);
 helper!(impl_for_specific_lit, crate::StringLit<String>, String, StringLit);
 helper!(impl_for_specific_lit, crate::ByteLit<String>, Byte, ByteLit);
 helper!(impl_for_specific_lit, crate::ByteStringLit<String>, ByteString, ByteStringLit);
 
+macro_rules! impl_from_tt_for_bool {
+    ([$($prefix:tt)*] => ) => {
+        impl TryFrom<$($prefix)* TokenTree> for crate::BoolLit {
+            type Error = InvalidToken;
+            fn try_from(tt: $($prefix)* TokenTree) -> Result<Self, Self::Error> {
+                let span = tt.span();
+                let actual = match tt {
+                    $($prefix)* TokenTree::Ident(ref ident) if ident.to_string() == "true"
+                        => return Ok(crate::BoolLit::True),
+                    $($prefix)* TokenTree::Ident(ref ident) if ident.to_string() == "false"
+                        => return Ok(crate::BoolLit::False),
+
+                    $($prefix)* TokenTree::Group(_) => TokenKind::Group,
+                    $($prefix)* TokenTree::Punct(_) => TokenKind::Punct,
+                    $($prefix)* TokenTree::Ident(_) => TokenKind::Ident,
+                    $($prefix)* TokenTree::Literal(ref lit) => kind_of(&Literal::from(lit)),
+                };
+
+                Err(InvalidToken {
+                    actual,
+                    expected: TokenKind::BoolLit,
+                    span: span.into(),
+                })
+            }
+        }
+    };
+}
+
+helper!(impl_from_tt_for_bool, );
 
 
 mod tests {
@@ -222,9 +233,6 @@ mod tests {
     //! let _ = litrs::Literal::try_from(give::<&proc_macro::TokenTree>());
     //!
     //!
-    //! let _ = litrs::BoolLit::try_from(give::<proc_macro::Literal>());
-    //! let _ = litrs::BoolLit::try_from(give::<&proc_macro::Literal>());
-    //!
     //! let _ = litrs::IntegerLit::try_from(give::<proc_macro::Literal>());
     //! let _ = litrs::IntegerLit::try_from(give::<&proc_macro::Literal>());
     //!
@@ -288,9 +296,6 @@ mod tests_proc_macro2 {
     //! let _ = litrs::Literal::try_from(give::<&proc_macro2::TokenTree>());
     //!
     //!
-    //! let _ = litrs::BoolLit::try_from(give::<proc_macro2::Literal>());
-    //! let _ = litrs::BoolLit::try_from(give::<&proc_macro2::Literal>());
-    //!
     //! let _ = litrs::IntegerLit::try_from(give::<proc_macro2::Literal>());
     //! let _ = litrs::IntegerLit::try_from(give::<&proc_macro2::Literal>());
     //!

diff --git a/src/lib.rs b/src/lib.rs
@@ -41,7 +41,9 @@
 //!
 //! **Note**: `true` and `false` are `Ident`s when passed to your proc macro.
 //! The `TryFrom<TokenTree>` impls check for those two special idents and
-//! return a `BoolLit` appropriately.
+//! return a `BoolLit` appropriately. For that reason, there is also no
+//! `TryFrom<proc_macro::Literal>` impl for `BoolLit`. The `proc_macro::Literal`
+//! simply cannot represent bool literals.
 //!
 //!
 //! # Examples

diff --git a/src/tests.rs b/src/tests.rs
@@ -104,7 +104,9 @@ fn proc_macro() {
     use proc_macro2::{
         self as pm2, TokenTree, Group, TokenStream, Delimiter, Spacing, Punct, Span, Ident,
     };
-    use crate::{BoolLit, ByteStringLit, CharLit, FloatLit, IntegerLit, StringLit, err::TokenKind};
+    use crate::{
+        BoolLit, ByteLit, ByteStringLit, CharLit, FloatLit, IntegerLit, StringLit, err::TokenKind
+    };
 
 
     macro_rules! assert_invalid_token {
@@ -189,13 +191,13 @@ fn proc_macro() {
         actual: TokenKind::FloatLit,
     );
     assert_invalid_token!(
-        BoolLit::try_from(pm_bytestr_lit.clone()),
-        expected: TokenKind::BoolLit,
+        ByteLit::try_from(pm_bytestr_lit.clone()),
+        expected: TokenKind::ByteLit,
         actual: TokenKind::ByteStringLit,
     );
     assert_invalid_token!(
-        BoolLit::try_from(pm_i16_lit.clone()),
-        expected: TokenKind::BoolLit,
+        ByteLit::try_from(pm_i16_lit.clone()),
+        expected: TokenKind::ByteLit,
         actual: TokenKind::IntegerLit,
     );
     assert_invalid_token!(