Keep label on moved spans and point at macro invocation on parse error

Author: estebank

src/librustc_errors/diagnostic.rs

@@ -139,6 +139,17 @@ impl Diagnostic {
         self
     }
 
+    pub fn replace_span_with(&mut self, after: Span) -> &mut Self {
+        let before = self.span.clone();
+        self.set_span(after);
+        for span_label in before.span_labels() {
+            if let Some(label) = span_label.label {
+                self.span_label(after, label);
+            }
+        }
+        self
+    }
+
     pub fn note_expected_found(&mut self,
                                label: &dyn fmt::Display,
                                expected: DiagnosticStyledString,

src/libsyntax/ext/tt/macro_rules.rs

@@ -53,20 +53,24 @@ impl<'a> ParserAnyMacro<'a> {
     pub fn make(mut self: Box<ParserAnyMacro<'a>>, kind: AstFragmentKind) -> AstFragment {
         let ParserAnyMacro { site_span, macro_ident, ref mut parser, arm_span } = *self;
         let fragment = panictry!(parser.parse_ast_fragment(kind, true).map_err(|mut e| {
-            if e.span.is_dummy() {  // Get around lack of span in error (#30128)
-                e.set_span(site_span);
-                e.span_label(site_span, "in this macro expansion");
-                e.span_label(arm_span, "in this macro arm");
-            } else if parser.token == token::Eof {  // (#52866)
-                e.set_span(parser.sess.source_map().next_point(parser.span));
-            }
-            if parser.token == token::Eof {
+            if parser.token == token::Eof && e.message().ends_with(", found `<eof>`") {
+                if !e.span.is_dummy() {  // early end of macro arm (#52866)
+                    e.replace_span_with(parser.sess.source_map().next_point(parser.span));
+                }
                 let msg = &e.message[0];
                 e.message[0] = (
                     msg.0.replace(", found `<eof>`", ", found the end of the macro arm"),
                     msg.1,
                 );
             }
+            if e.span.is_dummy() {  // Get around lack of span in error (#30128)
+                e.replace_span_with(site_span);
+                if parser.sess.source_map().span_to_filename(arm_span).is_real() {
+                    e.span_label(arm_span, "in this macro arm");
+                }
+            } else if !parser.sess.source_map().span_to_filename(parser.span).is_real() {
+                e.span_label(site_span, "in this macro invocation");
+            }
             e
         }));
 

src/test/ui/directory_ownership/macro-expanded-mod.rs

@@ -12,7 +12,6 @@
 
 macro_rules! mod_decl {
     ($i:ident) => { mod $i; }
-    //~^ ERROR Cannot declare a non-inline module inside a block
 }
 
 mod macro_expanded_mod_helper {
@@ -21,4 +20,5 @@ mod macro_expanded_mod_helper {
 
 fn main() {
     mod_decl!(foo);
+    //~^ ERROR Cannot declare a non-inline module inside a block
 }

src/test/ui/directory_ownership/macro-expanded-mod.stderr

@@ -1,8 +1,8 @@
 error: Cannot declare a non-inline module inside a block unless it has a path attribute
-  --> $DIR/macro-expanded-mod.rs:14:28
+  --> $DIR/macro-expanded-mod.rs:22:15
    |
-LL |     ($i:ident) => { mod $i; }
-   |                            ^
+LL |     mod_decl!(foo);
+   |               ^^^
 
 error: aborting due to previous error
 

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

@@ -26,7 +26,12 @@ error: expected one of `move`, `|`, or `||`, found the end of the macro arm
   --> <::edition_kw_macro_2015::passes_ident macros>:1:25
    |
 LL | ( $ i : ident ) => ( $ i )
-   |                         ^
+   |                         ^ expected one of `move`, `|`, or `||` here
+   | 
+  ::: $DIR/edition-keywords-2018-2015-parsing.rs:26:8
+   |
+LL |     if passes_ident!(async) == 1 {}
+   |        -------------------- in this macro invocation
 
 error: aborting due to 5 previous errors
 

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

@@ -26,7 +26,12 @@ error: expected one of `move`, `|`, or `||`, found the end of the macro arm
   --> <::edition_kw_macro_2018::passes_ident macros>:1:25
    |
 LL | ( $ i : ident ) => ( $ i )
-   |                         ^
+   |                         ^ expected one of `move`, `|`, or `||` here
+   | 
+  ::: $DIR/edition-keywords-2018-2018-parsing.rs:26:8
+   |
+LL |     if passes_ident!(async) == 1 {}
+   |        -------------------- in this macro invocation
 
 error: aborting due to 5 previous errors
 

src/test/ui/macros/macro-in-expression-context-2.stderr

@@ -5,7 +5,7 @@ LL | macro_rules! empty { () => () }
    |                            -- in this macro arm
 ...
 LL |         _ => { empty!() }
-   |                ^^^^^^^^ in this macro expansion
+   |                ^^^^^^^^ expected expression
 
 error: aborting due to previous error