Point at macro definition when no rules expect token

src/libsyntax/ext/base.rs

@@ -247,8 +247,13 @@ impl<F> AttrProcMacro for F
 
 /// Represents a thing that maps token trees to Macro Results
 pub trait TTMacroExpander {
-    fn expand<'cx>(&self, ecx: &'cx mut ExtCtxt, span: Span, input: TokenStream)
+    fn expand<'cx>(
-                   -> Box<dyn MacResult+'cx>;
+        &self,
+        ecx: &'cx mut ExtCtxt,
+        span: Span,
+        input: TokenStream,
+        def_span: Option<Span>,
+    ) -> Box<dyn MacResult+'cx>;
 }
 
 pub type MacroExpanderFn =
@@ -259,8 +264,13 @@ impl<F> TTMacroExpander for F
     where F: for<'cx> Fn(&'cx mut ExtCtxt, Span, &[tokenstream::TokenTree])
     -> Box<dyn MacResult+'cx>
 {
-    fn expand<'cx>(&self, ecx: &'cx mut ExtCtxt, span: Span, input: TokenStream)
+    fn expand<'cx>(
-                   -> Box<dyn MacResult+'cx> {
+        &self,
+        ecx: &'cx mut ExtCtxt,
+        span: Span,
+        input: TokenStream,
+        _def_span: Option<Span>,
+    ) -> Box<dyn MacResult+'cx> {
         struct AvoidInterpolatedIdents;
 
         impl Folder for AvoidInterpolatedIdents {

src/libsyntax/ext/expand.rs

@@ -764,7 +764,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                                                     edition) {
                     dummy_span
                 } else {
-                    kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
+                    kind.make_from(expander.expand(self.cx, span, mac.node.stream(), None))
                 }
             }
 
@@ -785,7 +785,12 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                                                     edition) {
                     dummy_span
                 } else {
-                    kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
+                    kind.make_from(expander.expand(
+                        self.cx,
+                        span,
+                        mac.node.stream(),
+                        def_info.map(|(_, s)| s),
+                    ))
                 }
             }
 

src/libsyntax/ext/tt/macro_rules.rs

@@ -74,16 +74,19 @@ struct MacroRulesMacroExpander {
 }
 
 impl TTMacroExpander for MacroRulesMacroExpander {
-    fn expand<'cx>(&self,
+    fn expand<'cx>(
+        &self,
         cx: &'cx mut ExtCtxt,
         sp: Span,
-                   input: TokenStream)
+        input: TokenStream,
-                   -> Box<dyn MacResult+'cx> {
+        def_span: Option<Span>,
+    ) -> Box<dyn MacResult+'cx> {
         if !self.valid {
             return DummyResult::any(sp);
         }
         generic_extension(cx,
                           sp,
+                          def_span,
                           self.name,
                           input,
                           &self.lhses,
@@ -99,6 +102,7 @@ fn trace_macros_note(cx: &mut ExtCtxt, sp: Span, message: String) {
 /// Given `lhses` and `rhses`, this is the new macro we create
 fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
                           sp: Span,
+                          def_span: Option<Span>,
                           name: ast::Ident,
                           arg: TokenStream,
                           lhses: &[quoted::TokenTree],
@@ -178,7 +182,14 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
     }
 
     let best_fail_msg = parse_failure_msg(best_fail_tok.expect("ran no matchers"));
-    let mut err = cx.struct_span_err(best_fail_spot.substitute_dummy(sp), &best_fail_msg);
+    let span = best_fail_spot.substitute_dummy(sp);
+    let mut err = cx.struct_span_err(span, &best_fail_msg);
+    err.span_label(span, best_fail_msg);
+    if let Some(sp) = def_span {
+        if cx.source_map().span_to_filename(sp).is_real() && !sp.is_dummy() {
+            err.span_label(sp, "when calling this macro");
+        }
+    }
 
     // Check whether there's a missing comma in this macro call, like `println!("{}" a);`
     if let Some((arg, comma_span)) = arg.add_comma() {
@@ -189,7 +200,7 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
             };
             match TokenTree::parse(cx, lhs_tt, arg.clone()) {
                 Success(_) => {
-                    if comma_span == DUMMY_SP {
+                    if comma_span.is_dummy() {
                         err.note("you might be missing a comma");
                     } else {
                         err.span_suggestion_short_with_applicability(

src/test/run-pass-fulldeps/auxiliary/plugin_args.rs

@@ -38,7 +38,8 @@ impl TTMacroExpander for Expander {
     fn expand<'cx>(&self,
                    ecx: &'cx mut ExtCtxt,
                    sp: Span,
-                   _: TokenStream) -> Box<MacResult+'cx> {
+                   _: TokenStream,
+                   _: Option<Span>) -> Box<MacResult+'cx> {
         let args = self.args.iter().map(|i| pprust::meta_list_item_to_string(i))
             .collect::<Vec<_>>().join(", ");
         MacEager::expr(ecx.expr_str(sp, Symbol::intern(&args)))

src/test/ui/editions/edition-keywords-2015-2015-parsing.stderr

@@ -2,13 +2,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2015-2015-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2015-2015-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: aborting due to 2 previous errors
 

src/test/ui/editions/edition-keywords-2015-2018-parsing.stderr

@@ -2,13 +2,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2015-2018-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2015-2018-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: aborting due to 2 previous errors
 

src/test/ui/editions/edition-keywords-2018-2015-parsing.stderr

@@ -14,13 +14,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2018-2015-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2018-2015-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: expected one of `move`, `|`, or `||`, found `<eof>`
   --> <::edition_kw_macro_2015::passes_ident macros>:1:22

src/test/ui/editions/edition-keywords-2018-2018-parsing.stderr

@@ -14,13 +14,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2018-2018-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2018-2018-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: expected one of `move`, `|`, or `||`, found `<eof>`
   --> <::edition_kw_macro_2018::passes_ident macros>:1:22

src/test/ui/empty/empty-comment.stderr

@@ -1,8 +1,13 @@
 error: unexpected end of macro invocation
   --> $DIR/empty-comment.rs:20:5
    |
+LL | / macro_rules! one_arg_macro {
+LL | |     ($fmt:expr) => (print!(concat!($fmt, "/n")));
+LL | | }
+   | |_- when calling this macro
+...
 LL |       one_arg_macro!(/**/); //~ ERROR unexpected end
-   |     ^^^^^^^^^^^^^^^^^^^^^
+   |       ^^^^^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
 
 error: aborting due to previous error
 

src/test/ui/fail-simple.stderr

@@ -2,7 +2,7 @@ error: no rules expected the token `@`
   --> $DIR/fail-simple.rs:12:12
    |
 LL |     panic!(@); //~ ERROR no rules expected the token `@`
-   |            ^
+   |            ^ no rules expected the token `@`
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-7970a.stderr

@@ -1,8 +1,13 @@
 error: unexpected end of macro invocation
   --> $DIR/issue-7970a.rs:16:5
    |
+LL | / macro_rules! one_arg_macro {
+LL | |     ($fmt:expr) => (print!(concat!($fmt, "/n")));
+LL | | }
+   | |_- when calling this macro
+...
 LL |       one_arg_macro!();
-   |     ^^^^^^^^^^^^^^^^^
+   |       ^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
 
 error: aborting due to previous error
 

src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr

@@ -51,20 +51,41 @@ LL |     ($(a)?*) => {}
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:41:11
    |
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | |     //~^ERROR using the `?` macro Kleene operator for
+LL | |     //~|ERROR expected `*` or `+`
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a?); //~ ERROR no rules expected the token `?`
-   |           ^
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:42:11
    |
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | |     //~^ERROR using the `?` macro Kleene operator for
+LL | |     //~|ERROR expected `*` or `+`
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:43:11
    |
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | |     //~^ERROR using the `?` macro Kleene operator for
+LL | |     //~|ERROR expected `*` or `+`
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a?a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+   |             ^ no rules expected the token `?`
 
 error: aborting due to 10 previous errors
 

src/test/ui/macros/macro-at-most-once-rep-2018.stderr

@@ -7,68 +7,123 @@ LL |     ($(a),?) => {} //~ERROR the `?` macro repetition operator
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:36:11
    |
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a?); //~ ERROR no rules expected the token `?`
-   |           ^
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:37:11
    |
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:38:11
    |
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a?a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+   |             ^ no rules expected the token `?`
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:40:5
    |
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barplus!(); //~ERROR unexpected end of macro invocation
-   |     ^^^^^^^^^^^
+   |       ^^^^^^^^^^^ unexpected end of macro invocation
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:41:14
    |
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barplus!(a); //~ERROR unexpected end of macro invocation
-   |              ^
+   |                ^ unexpected end of macro invocation
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:42:15
    |
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barplus!(a?); //~ ERROR no rules expected the token `?`
-   |               ^
+   |                 ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:43:15
    |
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barplus!(a?a); //~ ERROR no rules expected the token `?`
-   |               ^
+   |                 ^ no rules expected the token `?`
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:47:5
    |
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barstar!(); //~ERROR unexpected end of macro invocation
-   |     ^^^^^^^^^^^
+   |       ^^^^^^^^^^^ unexpected end of macro invocation
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:48:14
    |
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barstar!(a); //~ERROR unexpected end of macro invocation
-   |              ^
+   |                ^ unexpected end of macro invocation
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:49:15
    |
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barstar!(a?); //~ ERROR no rules expected the token `?`
-   |               ^
+   |                 ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:50:15
    |
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
 LL |       barstar!(a?a); //~ ERROR no rules expected the token `?`
-   |               ^
+   |                 ^ no rules expected the token `?`
 
 error: aborting due to 12 previous errors
 

src/test/ui/macros/macro-non-lifetime.stderr

@@ -1,8 +1,11 @@
 error: no rules expected the token `a`
   --> $DIR/macro-non-lifetime.rs:18:8
    |
+LL | macro_rules! m { ($x:lifetime) => { } }
+   | --------------------------------------- when calling this macro
+...
 LL |     m!(a);
-   |        ^
+   |        ^ no rules expected the token `a`
 
 error: aborting due to previous error
 

src/test/ui/macros/missing-comma.stderr

@@ -7,32 +7,68 @@ LL |     println!("{}" a);
 error: no rules expected the token `b`
   --> $DIR/missing-comma.rs:22:12
    |
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a b);
-   |           -^
+   |             -^ no rules expected the token `b`
    |             |
    |             help: missing comma here
 
 error: no rules expected the token `e`
   --> $DIR/missing-comma.rs:24:21
    |
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a, b, c, d e);
-   |                    -^
+   |                      -^ no rules expected the token `e`
    |                      |
    |                      help: missing comma here
 
 error: no rules expected the token `d`
   --> $DIR/missing-comma.rs:26:18
    |
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a, b, c d, e);
-   |                 -^
+   |                   -^ no rules expected the token `d`
    |                   |
    |                   help: missing comma here
 
 error: no rules expected the token `d`
   --> $DIR/missing-comma.rs:28:18
    |
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
 LL |       foo!(a, b, c d e);
-   |                  ^
+   |                    ^ no rules expected the token `d`
 
 error: aborting due to 5 previous errors
 

src/test/ui/macros/nonterminal-matching.stderr

@@ -2,7 +2,7 @@ error: no rules expected the token `enum E { }`
   --> $DIR/nonterminal-matching.rs:29:10
    |
 LL |     n!(a $nt_item b); //~ ERROR no rules expected the token `enum E { }`
-   |          ^^^^^^^^
+   |          ^^^^^^^^ no rules expected the token `enum E { }`
 ...
 LL | complex_nonterminal!(enum E {});
    | -------------------------------- in this macro invocation

src/test/ui/macros/trace_faulty_macros.stderr

@@ -1,8 +1,13 @@
 error: no rules expected the token `bcd`
   --> $DIR/trace_faulty_macros.rs:17:26
    |
-LL |         my_faulty_macro!(bcd); //~ ERROR no rules
+LL | / macro_rules! my_faulty_macro {
-   |                          ^^^
+LL | |     () => {
+LL | |         my_faulty_macro!(bcd); //~ ERROR no rules
+   | |                          ^^^ no rules expected the token `bcd`
+LL | |     };
+LL | | }
+   | |_- when calling this macro
 ...
 LL |       my_faulty_macro!();
    |       ------------------- in this macro invocation

src/test/ui/parser/macro/macro-doc-comments-1.stderr

@@ -1,8 +1,13 @@
 error: no rules expected the token `!`
   --> $DIR/macro-doc-comments-1.rs:16:5
    |
+LL | / macro_rules! outer {
+LL | |     (#[$outer:meta]) => ()
+LL | | }
+   | |_- when calling this macro
+...
 LL |       //! Inner
-   |     ^^^^^^^^^
+   |       ^^^^^^^^^ no rules expected the token `!`
 
 error: aborting due to previous error
 

src/test/ui/parser/macro/macro-doc-comments-2.stderr

@@ -1,8 +1,13 @@
 error: no rules expected the token `[`
   --> $DIR/macro-doc-comments-2.rs:16:5
    |
+LL | / macro_rules! inner {
+LL | |     (#![$inner:meta]) => ()
+LL | | }
+   | |_- when calling this macro
+...
 LL |       /// Outer
-   |     ^
+   |       ^ no rules expected the token `[`
 
 error: aborting due to previous error
 

src/test/ui/underscore-ident-matcher.stderr

@@ -1,8 +1,15 @@
 error: no rules expected the token `_`
   --> $DIR/underscore-ident-matcher.rs:18:19
    |
+LL | / macro_rules! identity {
+LL | |     ($i: ident) => (
+LL | |         $i
+LL | |     )
+LL | | }
+   | |_- when calling this macro
+...
 LL |       let identity!(_) = 10; //~ ERROR no rules expected the token `_`
-   |                   ^
+   |                     ^ no rules expected the token `_`
 
 error: aborting due to previous error
 

src/test/ui/vec/vec-macro-with-comma-only.stderr

@@ -2,7 +2,7 @@ error: no rules expected the token `,`
   --> $DIR/vec-macro-with-comma-only.rs:12:10
    |
 LL |     vec![,]; //~ ERROR no rules expected the token `,`
-   |          ^
+   |          ^ no rules expected the token `,`
 
 error: aborting due to previous error