[cfe-commits] [PATCH] Improved error recovery in for-statement

[Richard Smith]

Hi,

The attached patch improves diagnostics error recovery in for-statements.
Examples:

Before:

for.cpp:8:11: error: expected ';' in 'for' statement specifier
  for (n  0; n < 10; n++); // expected-error {{expected '=' in 'for'}}
          ^
for.cpp:8:8: warning: expression result unused
  for (n  0; n < 10; n++); // expected-error {{expected '=' in 'for'}}
       ^

After:

for.cpp:8:11: error: expected '=' in 'for' init statement
  for (n  0; n < 10; n++); // expected-error {{expected '=' in 'for'}}
          ^
          =


Before (note that this error currently causes clang to get confused about
the following statement):

for.cpp:9:14: error: expected ';' in 'for' statement specifier
  for (n = 0 n < 10; n++); // expected-error {{expected ';' in 'for'}}
             ^
for.cpp:9:25: error: expected ';' in 'for' statement specifier
  for (n = 0 n < 10; n++); // expected-error {{expected ';' in 'for'}}
                        ^
for.cpp:10:3: error: expected expression
  for (n = 0; n < 10 n++); // expected-error {{expected ';' in 'for'}}
  ^
for.cpp:10:3: error: expected ')'
for.cpp:9:7: note: to match this '('
  for (n = 0 n < 10; n++); // expected-error {{expected ';' in 'for'}}
      ^

After:

for.cpp:9:14: error: expected ';' in 'for' statement specifier
  for (n = 0 n < 10; n++); // expected-error {{expected ';' in 'for'}}
             ^
             ;


Before (an extreme case):

for.cpp:20:10: error: expected ';' in 'for' statement specifier
  for (n 0 n < 10 n++); // expected-error {{expected '=' in 'for'}}
expected-error 2{{expected ';' in 'for'}}
         ^
for.cpp:20:22: error: expected expression
  for (n 0 n < 10 n++); // expected-error {{expected '=' in 'for'}}
expected-error 2{{expected ';' in 'for'}}
                     ^
for.cpp:22:3: error: expected expression
  for (intt n = 0; n < 10; ++n); // expected-error {{undeclared identifier
'intt'}}
  ^
for.cpp:22:3: error: expected ')'
for.cpp:20:7: note: to match this '('
  for (n 0 n < 10 n++); // expected-error {{expected '=' in 'for'}}
expected-error 2{{expected ';' in 'for'}}
      ^
for.cpp:20:8: warning: expression result unused
  for (n 0 n < 10 n++); // expected-error {{expected '=' in 'for'}}
expected-error 2{{expected ';' in 'for'}}
       ^

After:

../src/tools/clang/test/Parser/for.cpp:20:10: error: expected '=' in 'for'
init statement
  for (n 0 n < 10 n++); // expected-error {{expected '=' in 'for'}}
expected-error 2{{expected ';' in 'for'}}
         ^
         =
../src/tools/clang/test/Parser/for.cpp:20:12: error: expected ';' in 'for'
statement specifier
  for (n 0 n < 10 n++); // expected-error {{expected '=' in 'for'}}
expected-error 2{{expected ';' in 'for'}}
           ^
           ;
../src/tools/clang/test/Parser/for.cpp:20:19: error: expected ';' in 'for'
statement specifier
  for (n 0 n < 10 n++); // expected-error {{expected '=' in 'for'}}
expected-error 2{{expected ';' in 'for'}}
                  ^
                  ;

The patch can be viewed online here: http://codereview.appspot.com/3992046/

Please let me know what I need to fix in order to get this committed.

Thanks!
Richard
-------------- next part --------------
A non-text attachment was scrubbed...
Name: clang-for-error.patch
Type: text/x-patch
Size: 5491 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20110125/4a3cc2f2/attachment.bin>