syntax: Remove redundant span from ast::Mac

Also remove a couple of redundant `visit_mac` asserts

src/librustc_parse/parser/expr.rs

@@ -927,7 +927,6 @@ impl<'a> Parser<'a> {
                         ex = ExprKind::Mac(Mac {
                             path,
                             args,
-                            span: lo.to(hi),
                             prior_type_ascription: self.last_type_ascription,
                         });
                     } else if self.check(&token::OpenDelim(token::Brace)) {

src/librustc_parse/parser/item.rs

@@ -432,8 +432,6 @@ impl<'a> Parser<'a> {
             let prev_span = self.prev_span;
             self.complain_if_pub_macro(&visibility.node, prev_span);
 
-            let mac_lo = self.token.span;
-
             // Item macro
             let path = self.parse_path(PathStyle::Mod)?;
             self.expect(&token::Not)?;
@@ -446,7 +444,6 @@ impl<'a> Parser<'a> {
             let mac = Mac {
                 path,
                 args,
-                span: mac_lo.to(hi),
                 prior_type_ascription: self.last_type_ascription,
             };
             let item =
@@ -499,7 +496,6 @@ impl<'a> Parser<'a> {
         if self.token.is_path_start() &&
                 !(self.is_async_fn() && self.token.span.rust_2015()) {
             let prev_span = self.prev_span;
-            let lo = self.token.span;
             let path = self.parse_path(PathStyle::Mod)?;
 
             if path.segments.len() == 1 {
@@ -525,7 +521,6 @@ impl<'a> Parser<'a> {
             Ok(Some(Mac {
                 path,
                 args,
-                span: lo.to(self.prev_span),
                 prior_type_ascription: self.last_type_ascription,
             }))
         } else {

src/librustc_parse/parser/pat.rs

@@ -338,7 +338,7 @@ impl<'a> Parser<'a> {
                     (None, self.parse_path(PathStyle::Expr)?)
                 };
                 match self.token.kind {
-                    token::Not if qself.is_none() => self.parse_pat_mac_invoc(lo, path)?,
+                    token::Not if qself.is_none() => self.parse_pat_mac_invoc(path)?,
                     token::DotDotDot | token::DotDotEq | token::DotDot => {
                         self.parse_pat_range_starting_with_path(lo, qself, path)?
                     }
@@ -593,13 +593,12 @@ impl<'a> Parser<'a> {
     }
 
     /// Parse macro invocation
-    fn parse_pat_mac_invoc(&mut self, lo: Span, path: Path) -> PResult<'a, PatKind> {
+    fn parse_pat_mac_invoc(&mut self, path: Path) -> PResult<'a, PatKind> {
         self.bump();
         let args = self.parse_mac_args()?;
         let mac = Mac {
             path,
             args,
-            span: lo.to(self.prev_span),
             prior_type_ascription: self.last_type_ascription,
         };
         Ok(PatKind::Mac(mac))

src/librustc_parse/parser/stmt.rs

@@ -106,7 +106,6 @@ impl<'a> Parser<'a> {
             let mac = Mac {
                 path,
                 args,
-                span: lo.to(hi),
                 prior_type_ascription: self.last_type_ascription,
             };
             let kind = if delim == token::Brace ||
@@ -130,7 +129,7 @@ impl<'a> Parser<'a> {
                 self.warn_missing_semicolon();
                 StmtKind::Mac(P((mac, style, attrs.into())))
             } else {
-                let e = self.mk_expr(mac.span, ExprKind::Mac(mac), ThinVec::new());
+                let e = self.mk_expr(lo.to(hi), ExprKind::Mac(mac), ThinVec::new());
                 let e = self.maybe_recover_from_bad_qpath(e, true)?;
                 let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
                 let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;

src/librustc_parse/parser/ty.rs

@@ -181,7 +181,6 @@ impl<'a> Parser<'a> {
                 let mac = Mac {
                     path,
                     args,
-                    span: lo.to(self.prev_span),
                     prior_type_ascription: self.last_type_ascription,
                 };
                 TyKind::Mac(mac)

src/librustc_passes/ast_validation.rs

@@ -737,14 +737,6 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             |this| visit::walk_enum_def(this, enum_definition, generics, item_id))
     }
 
-    fn visit_mac(&mut self, mac: &Mac) {
-        // when a new macro kind is added but the author forgets to set it up for expansion
-        // because that's the only part that won't cause a compiler error
-        self.session.diagnostic()
-            .span_bug(mac.span, "macro invocation missed in expansion; did you forget to override \
-                                 the relevant `fold_*()` method in `PlaceholderExpander`?");
-    }
-
     fn visit_impl_item(&mut self, ii: &'a ImplItem) {
         if let ImplItemKind::Method(ref sig, _) = ii.kind {
             self.check_fn_decl(&sig.decl);

src/librustc_save_analysis/dump_visitor.rs

@@ -1515,14 +1515,6 @@ impl<'l, 'tcx> Visitor<'l> for DumpVisitor<'l, 'tcx> {
         }
     }
 
-    fn visit_mac(&mut self, mac: &'l ast::Mac) {
-        // These shouldn't exist in the AST at this point, log a span bug.
-        span_bug!(
-            mac.span,
-            "macro invocation should have been expanded out of AST"
-        );
-    }
-
     fn visit_pat(&mut self, p: &'l ast::Pat) {
         self.process_macro_use(p.span);
         self.process_pat(p);

src/libsyntax/ast.rs

@@ -1379,10 +1379,15 @@ pub enum Movability {
 pub struct Mac {
     pub path: Path,
     pub args: P<MacArgs>,
-    pub span: Span,
     pub prior_type_ascription: Option<(Span, bool)>,
 }
 
+impl Mac {
+    pub fn span(&self) -> Span {
+        self.path.span.to(self.args.span().unwrap_or(self.path.span))
+    }
+}
+
 /// Arguments passed to an attribute or a function-like macro.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum MacArgs {
@@ -1403,6 +1408,14 @@ impl MacArgs {
         }
     }
 
+    pub fn span(&self) -> Option<Span> {
+        match *self {
+            MacArgs::Empty => None,
+            MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
+            MacArgs::Eq(eq_span, ref tokens) => Some(eq_span.to(tokens.span().unwrap_or(eq_span))),
+        }
+    }
+
     /// Tokens inside the delimiters or after `=`.
     /// Proc macros see these tokens, for example.
     pub fn inner_tokens(&self) -> TokenStream {
@@ -1432,12 +1445,6 @@ impl MacArgs {
     }
 }
 
-impl Mac {
-    pub fn stream(&self) -> TokenStream {
-        self.args.inner_tokens()
-    }
-}
-
 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
 pub enum MacDelimiter {
     Parenthesis,

src/libsyntax/mut_visit.rs

@@ -580,10 +580,9 @@ pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
 }
 
 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut Mac, vis: &mut T) {
-    let Mac { path, args, span, prior_type_ascription: _ } = mac;
+    let Mac { path, args, prior_type_ascription: _ } = mac;
     vis.visit_path(path);
     visit_mac_args(args, vis);
-    vis.visit_span(span);
 }
 
 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {

src/libsyntax/print/pprust.rs

@@ -1772,9 +1772,9 @@ impl<'a> State<'a> {
             true,
             None,
             m.args.delim(),
-            m.stream(),
+            m.args.inner_tokens(),
             true,
-            m.span,
+            m.span(),
         );
     }
 

src/libsyntax/tokenstream.rs

@@ -225,6 +225,14 @@ impl TokenStream {
         self.0.len()
     }
 
+    pub fn span(&self) -> Option<Span> {
+        match &**self.0 {
+            [] => None,
+            [(tt, _)] => Some(tt.span()),
+            [(tt_start, _), .., (tt_end, _)] => Some(tt_start.span().to(tt_end.span())),
+        }
+    }
+
     pub fn from_streams(mut streams: SmallVec<[TokenStream; 2]>) -> TokenStream {
         match streams.len() {
             0 => TokenStream::default(),

src/libsyntax_expand/expand.rs

@@ -597,13 +597,13 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             InvocationKind::Bang { mac, .. } => match ext {
                 SyntaxExtensionKind::Bang(expander) => {
                     self.gate_proc_macro_expansion_kind(span, fragment_kind);
-                    let tok_result = expander.expand(self.cx, span, mac.stream());
+                    let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
                     self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
                 }
                 SyntaxExtensionKind::LegacyBang(expander) => {
                     let prev = self.cx.current_expansion.prior_type_ascription;
                     self.cx.current_expansion.prior_type_ascription = mac.prior_type_ascription;
-                    let tok_result = expander.expand(self.cx, span, mac.stream());
+                    let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
                     let result = if let Some(result) = fragment_kind.make_from(tok_result) {
                         result
                     } else {

src/libsyntax_expand/parse/tests.rs

@@ -272,7 +272,7 @@ fn ttdelim_span() {
             "foo!( fn main() { body } )".to_string(), &sess).unwrap();
 
         let tts: Vec<_> = match expr.kind {
-            ast::ExprKind::Mac(ref mac) => mac.stream().trees().collect(),
+            ast::ExprKind::Mac(ref mac) => mac.args.inner_tokens().trees().collect(),
             _ => panic!("not a macro"),
         };
 

src/libsyntax_expand/placeholders.rs

@@ -17,7 +17,6 @@ pub fn placeholder(kind: AstFragmentKind, id: ast::NodeId, vis: Option<ast::Visi
         ast::Mac {
             path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
             args: P(ast::MacArgs::Empty),
-            span: DUMMY_SP,
             prior_type_ascription: None,
         }
     }

src/libsyntax_ext/assert.rs

@@ -39,7 +39,6 @@ pub fn expand_assert<'cx>(
     let panic_call = Mac {
         path: Path::from_ident(Ident::new(sym::panic, sp)),
         args,
-        span: sp,
         prior_type_ascription: None,
     };
     let if_expr = cx.expr_if(

src/libsyntax_ext/deriving/generic/mod.rs

@@ -340,14 +340,12 @@ pub fn combine_substructure(f: CombineSubstructureFunc<'_>)
 fn find_type_parameters(
     ty: &ast::Ty,
     ty_param_names: &[ast::Name],
-    span: Span,
     cx: &ExtCtxt<'_>,
 ) -> Vec<P<ast::Ty>> {
     use syntax::visit;
 
     struct Visitor<'a, 'b> {
         cx: &'a ExtCtxt<'b>,
-        span: Span,
         ty_param_names: &'a [ast::Name],
         types: Vec<P<ast::Ty>>,
     }
@@ -366,18 +364,11 @@ fn find_type_parameters(
         }
 
         fn visit_mac(&mut self, mac: &ast::Mac) {
-            let span = mac.span.with_ctxt(self.span.ctxt());
-            self.cx.span_err(span, "`derive` cannot be used on items with type macros");
+            self.cx.span_err(mac.span(), "`derive` cannot be used on items with type macros");
         }
     }
 
-    let mut visitor = Visitor {
-        ty_param_names,
-        types: Vec::new(),
-        span,
-        cx,
-    };
-
+    let mut visitor = Visitor { cx, ty_param_names, types: Vec::new() };
     visit::Visitor::visit_ty(&mut visitor, ty);
 
     visitor.types
@@ -605,7 +596,7 @@ impl<'a> TraitDef<'a> {
                     .collect();
 
                 for field_ty in field_tys {
-                    let tys = find_type_parameters(&field_ty, &ty_param_names, self.span, cx);
+                    let tys = find_type_parameters(&field_ty, &ty_param_names, cx);
 
                     for ty in tys {
                         // if we have already handled this type, skip it