Make Parser::num_bump_calls 0-indexed.

Currently in `collect_tokens_trailing_token`, `start_pos` and `end_pos`
are 1-indexed by `replace_ranges` is 0-indexed, which is really
confusing. Making them both 0-indexed makes debugging much easier.

Author: nnethercote

compiler/rustc_parse/src/parser/mod.rs

@@ -425,6 +425,11 @@ impl<'a> Parser<'a> {
         // Make parser point to the first token.
         parser.bump();
 
+        // Change this from 1 back to 0 after the bump. This eases debugging of
+        // `Parser::collect_tokens_trailing_token` nicer because it makes the
+        // token positions 0-indexed which is nicer than 1-indexed.
+        parser.num_bump_calls = 0;
+
         parser
     }
 

compiler/rustc_parse/src/parser/tests.rs

@@ -1522,7 +1522,7 @@ fn debug_lookahead() {
         },
     },
     tokens: [],
-    approx_token_stream_pos: 1,
+    approx_token_stream_pos: 0,
     ..
 }"
         );
@@ -1566,7 +1566,7 @@ fn debug_lookahead() {
             Parenthesis,
         ),
     ],
-    approx_token_stream_pos: 1,
+    approx_token_stream_pos: 0,
     ..
 }"
         );
@@ -1631,7 +1631,7 @@ fn debug_lookahead() {
         Semi,
         Eof,
     ],
-    approx_token_stream_pos: 1,
+    approx_token_stream_pos: 0,
     ..
 }"
         );
@@ -1663,7 +1663,7 @@ fn debug_lookahead() {
             No,
         ),
     ],
-    approx_token_stream_pos: 9,
+    approx_token_stream_pos: 8,
     ..
 }"
         );
@@ -1701,7 +1701,7 @@ fn debug_lookahead() {
             No,
         ),
     ],
-    approx_token_stream_pos: 9,
+    approx_token_stream_pos: 8,
     ..
 }"
         );
@@ -1728,7 +1728,7 @@ fn debug_lookahead() {
     tokens: [
         Eof,
     ],
-    approx_token_stream_pos: 15,
+    approx_token_stream_pos: 14,
     ..
 }"
         );