ast-exporter: include full final token in decl source ranges

Clang's SourceRange ends at the beginning of the final token, but this is not useful if we want to look at every character of a declaration, as we may when considering the spelling of the corresponding C definition

Author: fw-immunant

c2rust-ast-exporter/src/AstExporter.cpp

@@ -830,9 +830,13 @@ class TranslateASTVisitor final
         Decl *ast, ASTEntryTag tag, const std::vector<void *> &childIds,
         const QualType T,
         std::function<void(CborEncoder *)> extra = [](CborEncoder *) {}) {
+        auto &Mgr = Context->getSourceManager();
         auto rvalue = false;
         auto encodeMacroExpansions = false;
-        encode_entry_raw(ast, tag, ast->getSourceRange(), T, rvalue,
+        auto charRange = clang::CharSourceRange::getCharRange(ast->getSourceRange());
+        // Extend the range to include the entire final token.
+        charRange.setEnd(clang::Lexer::getLocForEndOfToken(ast->getSourceRange().getEnd(), 0, Mgr, Context->getLangOpts()));
+        encode_entry_raw(ast, tag, charRange.getAsRange(), T, rvalue,
                          isVaList(ast, T), encodeMacroExpansions, childIds, extra);
     }
 
@@ -1998,7 +2002,13 @@ class TranslateASTVisitor final
 
         // We prefer non-implicit decls for their type information.
         auto functionType = paramsFD->getType();
-        auto span = paramsFD->getSourceRange();
+        auto &Mgr = Context->getSourceManager();
+        auto rvalue = false;
+        auto encodeMacroExpansions = false;
+        auto charRange = clang::CharSourceRange::getCharRange(FD->getSourceRange());
+        // Extend the range to include the entire final token.
+        charRange.setEnd(clang::Lexer::getLocForEndOfToken(FD->getSourceRange().getEnd(), 0, Mgr, Context->getLangOpts()));
+        auto span = charRange.getAsRange();
         encode_entry(
             FD, TagFunctionDecl, span, childIds, functionType,
             [this, FD](CborEncoder *array) {
@@ -2119,7 +2129,12 @@ class TranslateASTVisitor final
         // type
         auto T = def->getType();
 
-        auto loc = is_defn ? def->getLocation() : VD->getLocation();
+        auto loc = is_defn ? def->getSourceRange() : VD->getSourceRange();
+        auto &Mgr = Context->getSourceManager();
+        auto charRange = clang::CharSourceRange::getCharRange(loc);
+        // Extend the range to include the entire final token.
+        charRange.setEnd(clang::Lexer::getLocForEndOfToken(loc.getEnd(), 0, Mgr, Context->getLangOpts()));
+        loc = charRange.getAsRange();
 
         encode_entry(
             VD, TagVarDecl, loc, childIds, T,