Remove default macro transparencies

All transparancies are passed explicitly now.
Also remove `#[rustc_macro_transparency]` annotations from built-in macros, they are no longer used.
`#[rustc_macro_transparency]` only makes sense for declarative macros now.

Author: petrochenkov

src/libcore/macros.rs

@@ -734,7 +734,6 @@ pub(crate) mod builtin {
     #[allow_internal_unstable(fmt_internals)]
     #[rustc_builtin_macro]
     #[macro_export]
-    #[rustc_macro_transparency = "opaque"]
     macro_rules! format_args {
         ($fmt:expr) => ({ /* compiler built-in */ });
         ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ })
@@ -747,7 +746,6 @@ pub(crate) mod builtin {
     #[allow_internal_unstable(fmt_internals)]
     #[rustc_builtin_macro]
     #[macro_export]
-    #[rustc_macro_transparency = "opaque"]
     macro_rules! format_args_nl {
         ($fmt:expr) => ({ /* compiler built-in */ });
         ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ })
@@ -1235,42 +1233,36 @@ pub(crate) mod builtin {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro test($item:item) { /* compiler built-in */ }
 
     /// Attribute macro applied to a function to turn it into a benchmark test.
     #[unstable(feature = "test", issue = "50297",
                reason = "`bench` is a part of custom test frameworks which are unstable")]
     #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro bench($item:item) { /* compiler built-in */ }
 
     /// An implementation detail of the `#[test]` and `#[bench]` macros.
     #[unstable(feature = "custom_test_frameworks", issue = "50297",
                reason = "custom test frameworks are an unstable feature")]
     #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro test_case($item:item) { /* compiler built-in */ }
 
     /// Attribute macro applied to a static to register it as a global allocator.
     #[stable(feature = "global_allocator", since = "1.28.0")]
     #[allow_internal_unstable(rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro global_allocator($item:item) { /* compiler built-in */ }
 
     /// Unstable implementation detail of the `rustc` compiler, do not use.
     #[rustc_builtin_macro]
-    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(core_intrinsics, libstd_sys_internals)]
     pub macro RustcDecodable($item:item) { /* compiler built-in */ }
 
     /// Unstable implementation detail of the `rustc` compiler, do not use.
     #[rustc_builtin_macro]
-    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(core_intrinsics)]
     pub macro RustcEncodable($item:item) { /* compiler built-in */ }

src/librustc/ich/impls_syntax.rs

@@ -402,7 +402,6 @@ impl_stable_hash_for!(struct ::syntax_pos::hygiene::ExpnData {
     parent -> _,
     call_site,
     def_site,
-    default_transparency,
     allow_internal_unstable,
     allow_internal_unsafe,
     local_inner_macros,

src/libsyntax/ext/base.rs

@@ -549,8 +549,6 @@ pub struct SyntaxExtension {
     pub kind: SyntaxExtensionKind,
     /// Span of the macro definition.
     pub span: Span,
-    /// Hygienic properties of spans produced by this macro by default.
-    pub default_transparency: Transparency,
     /// Whitelist of unstable features that are treated as stable inside this macro.
     pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
     /// Suppresses the `unsafe_code` lint for code produced by this macro.
@@ -572,22 +570,6 @@ pub struct SyntaxExtension {
     pub is_derive_copy: bool,
 }
 
-impl SyntaxExtensionKind {
-    /// When a syntax extension is constructed,
-    /// its transparency can often be inferred from its kind.
-    fn default_transparency(&self) -> Transparency {
-        match self {
-            SyntaxExtensionKind::Bang(..) |
-            SyntaxExtensionKind::Attr(..) |
-            SyntaxExtensionKind::Derive(..) |
-            SyntaxExtensionKind::NonMacroAttr { .. } => Transparency::Opaque,
-            SyntaxExtensionKind::LegacyBang(..) |
-            SyntaxExtensionKind::LegacyAttr(..) |
-            SyntaxExtensionKind::LegacyDerive(..) => Transparency::SemiTransparent,
-        }
-    }
-}
-
 impl SyntaxExtension {
     /// Returns which kind of macro calls this syntax extension.
     pub fn macro_kind(&self) -> MacroKind {
@@ -606,7 +588,6 @@ impl SyntaxExtension {
     pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
         SyntaxExtension {
             span: DUMMY_SP,
-            default_transparency: kind.default_transparency(),
             allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,
@@ -646,7 +627,6 @@ impl SyntaxExtension {
             parent,
             call_site,
             def_site: self.span,
-            default_transparency: self.default_transparency,
             allow_internal_unstable: self.allow_internal_unstable.clone(),
             allow_internal_unsafe: self.allow_internal_unsafe,
             local_inner_macros: self.local_inner_macros,

src/libsyntax/ext/tt/macro_rules.rs

@@ -478,7 +478,6 @@ pub fn compile(
     SyntaxExtension {
         kind: SyntaxExtensionKind::LegacyBang(expander),
         span: def.span,
-        default_transparency: transparency,
         allow_internal_unstable,
         allow_internal_unsafe: attr::contains_name(&def.attrs, sym::allow_internal_unsafe),
         local_inner_macros,

src/libsyntax_pos/hygiene.rs

@@ -550,8 +550,7 @@ impl Span {
     /// The returned span belongs to the created expansion and has the new properties,
     /// but its location is inherited from the current span.
     pub fn fresh_expansion(self, expn_data: ExpnData) -> Span {
-        let transparency = expn_data.default_transparency;
-        self.fresh_expansion_with_transparency(expn_data, transparency)
+        self.fresh_expansion_with_transparency(expn_data, Transparency::SemiTransparent)
     }
 
     pub fn fresh_expansion_with_transparency(
@@ -591,8 +590,6 @@ pub struct ExpnData {
     /// The span of the macro definition (possibly dummy).
     /// This span serves only informational purpose and is not used for resolution.
     pub def_site: Span,
-    /// Transparency used by `apply_mark` for the expansion with this expansion data by default.
-    pub default_transparency: Transparency,
     /// List of #[unstable]/feature-gated features that the macro is allowed to use
     /// internally without forcing the whole crate to opt-in
     /// to them.
@@ -615,7 +612,6 @@ impl ExpnData {
             parent: ExpnId::root(),
             call_site,
             def_site: DUMMY_SP,
-            default_transparency: Transparency::SemiTransparent,
             allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,