Note, not trying to address every last error, just some obvious/easy ones.
```
/usr/local/google/home/jperkins/dev/carbon-lang/common/string_helpers.cpp:200:13: warning: prefer transparent functors 'less_equal<>' [modernize-use-transparent-functors]
auto le = std::less_equal<const char*>();
^
/usr/local/google/home/jperkins/dev/carbon-lang/toolchain/semantics/nodes/function.h:22:45: warning: pass by value and use std::move [modernize-pass-by-value]
Function(ParseTree::Node node, NodeId id, llvm::SmallVector<NodeRef> body)
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/ast/declaration.cpp:230:14: warning: static member accessed through instance [readability-static-accessed-through-instance]
return cast<SelfDeclaration>(declaration).name();
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/interpreter/type_checker.cpp:1104:33: warning: std::move of the variable 'impl' of the trivially-copyable type 'ConstraintType::ImplConstraint' has no effect [performance-move-const-arg]
impl_constraints_.push_back(std::move(impl));
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/interpreter/type_checker.cpp:1145:36: warning: std::move of the variable 'rewrite' of the trivially-copyable type 'ConstraintType::RewriteConstraint' has no effect [performance-move-const-arg]
rewrite_constraints_.push_back(std::move(rewrite));
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/interpreter/type_checker.cpp:1156:32: warning: std::move of the variable 'context' of the trivially-copyable type 'ConstraintType::LookupContext' has no effect [performance-move-const-arg]
lookup_contexts_.push_back(std::move(context));
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/fuzzing/fuzzverter.cpp:74:42: warning: argument name 'trace' in comment does not match parameter name 'parser_debug' [bugprone-argument-comment]
/*trace=*/false);
^
./explorer/syntax/parse.h:19:17: note: 'parser_debug' declared here
bool parser_debug) -> ErrorOr<Carbon::AST>;
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/fuzzing/proto_to_carbon_test.cpp:34:55: warning: argument name 'trace' in comment does not match parameter name 'parser_debug' [bugprone-argument-comment]
const ErrorOr<AST> ast = Carbon::Parse(&arena, f, /*trace=*/false);
^
./explorer/syntax/parse.h:19:17: note: 'parser_debug' declared here
bool parser_debug) -> ErrorOr<Carbon::AST>;
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/fuzzing/proto_to_carbon_test.cpp:42:41: warning: argument name 'trace' in comment does not match parameter name 'parser_debug' [bugprone-argument-comment]
&arena, f, source_from_proto, /*trace=*/false);
^
./explorer/syntax/parse.h:25:59: note: 'parser_debug' declared here
std::string_view file_contents, bool parser_debug)
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/syntax/parse_test.cpp:27:60: warning: argument name 'trace' in comment does not match parameter name 'parser_debug' [bugprone-argument-comment]
ParseFromString(&arena, "file.carbon", FileContents, /*trace=*/false);
^
./explorer/syntax/parse.h:25:59: note: 'parser_debug' declared here
std::string_view file_contents, bool parser_debug)
^
/usr/local/google/home/jperkins/dev/carbon-lang/migrate_cpp/cpp_refactoring/var_decl.cpp:57:58: warning: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation]
segments.push_back({type_loc_class, qual_str + " " + range_str});
^
/usr/local/google/home/jperkins/dev/carbon-lang/explorer/fuzzing/ast_to_proto_test.cpp:105:55: warning: argument name 'trace' in comment does not match parameter name 'parser_debug' [bugprone-argument-comment]
const ErrorOr<AST> ast = Carbon::Parse(&arena, f, /*trace=*/false);
^
./explorer/syntax/parse.h:19:17: note: 'parser_debug' declared here
bool parser_debug) -> ErrorOr<Carbon::AST>;
^
```
This replaces GetAstMatcher with AddMatcher because cxxForRangeStmt is a StatementMatcher. addMatcher has multiple definitions (https://clang.llvm.org/doxygen/classclang_1_1ast__matchers_1_1MatchFinder.html) and so this approach allows using the right addMatcher without writing per-call overloads.
To handle the `var`, I'm considering something like moving VarDecl logic into a VarMatcherBase so that I can just use CXXForRangeStmt's getLoopVariable. The problem is a for-range statement has multiple VarDecls, and getLoopVariable may be the easiest way to identify the real one.
Range-based for loops remain messed up -- I'm just disabling the test here and turning a blind eye.
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
TODOs in the test for known issues.
I may switch the approach to getting the variable type (on examination, this isn't working quite as well as I'd thought) but for now I think it's okay. I had an earlier approach though that may work better overall -- I'd been thinking this would work better, but as you can see in the null check for type information, I think I missed a key point.
Anyways, what'd really been vexing me was `int i, j` which I think I handle passably well now. There's obviously room for improvement, but given I've been going at this for a couple days now, I thought it best to checkpoint where I was.
This also includes some related framework changes to fix bumps I was running into. Overall the tool should operate a bit more smoothly with these changes. There are still issues with overlapping replacements, but I think it's primarily with range-based for loops which I just need to take some time to fix.
Jon Ross-Perkins
Jon Meow
