[flang][nfc] Fix comments, remove needless API, tweak script

[klausler]

Summary

• Remove an unimplemented and unused member function declaration
• Remove a misleading comment about an unrelated constraint number
• Fix a comment
• Add f18 crash message to "flang" driver script

[tskeith]

flang/tools/f18/flang

18

This will have exit status 0 even in error cases because echo is the last command. So it should have exit 1 in the else part.

I think it would be clearer without the empty then part:

if ! $wd/bin/f18 $opts "$@"; then
  echo flang: in $PWD, f18 failed with exit status $?: $wd/bin/f18 $opts "$@" >&2
  exit 1
fi

[klausler]

Address review comment.

flang/include/flang/Parser/provenance.h

   std::string GetPath(Provenance) const; // __FILE__
   int GetLineNumber(Provenance) const; // __LINE__
   Provenance CompilerInsertionProvenance(char ch);
-  Provenance CompilerInsertionProvenance(const char *, std::size_t);
   ProvenanceRange IntersectionWithSourceFiles(ProvenanceRange) const;
   llvm::raw_ostream &Dump(llvm::raw_ostream &) const;
 

flang/include/flang/Semantics/symbol.h

 };
 
 // Record the USE of a symbol: location is where (USE statement or renaming);
-// symbol is the USEd module.
+// symbol is in the USEd module.
 class UseDetails {
 public:
   UseDetails(const SourceName &location, const Symbol &symbol)

flang/lib/Semantics/assignment.cpp

       const Scope &scope{context_.FindScope(lhsLoc)};
       if (auto whyNot{WhyNotModifiable(lhsLoc, lhs, scope, true)}) {
         if (auto *msg{Say(lhsLoc,
-                "Left-hand side of assignment is not modifiable"_err_en_US)}) { // C1158
+                "Left-hand side of assignment is not modifiable"_err_en_US)}) {
           msg->Attach(*whyNot);
         }
       }

flang/tools/f18/flang

 if [[ ! -d $module_dir ]]; then
   module_dir=$wd/tools/flang/include/flang
 fi
-$wd/bin/f18 -module-suffix .f18.mod -intrinsic-module-directory $module_dir "$@"
+opts="-module-suffix .f18.mod -intrinsic-module-directory $module_dir"
+if $wd/bin/f18 $opts "$@"
+then :
+else echo flang: in $PWD, f18 failed with exit status $?: $wd/bin/f18 $opts "$@" >&2
+fi