[Parser][NFC] Small code cleanups (#4729)

Apply cleanups suggested by aheejin in post-merge code review of previous
parser PRs.

5 files changed, 19 insertions, 16 deletions

diff --git a/src/wasm/wasm-io.cpp b/src/wasm/wasm-io.cpp
index 55892975b..90f267e9b 100644
--- a/src/wasm/wasm-io.cpp
+++ b/src/wasm/wasm-io.cpp
@@ -24,12 +24,12 @@
 // binary.
 //
 
+#include "wasm-io.h"
 #include "support/debug.h"
 #include "wasm-binary.h"
 #include "wasm-s-parser.h"
 #include "wat-parser.h"
 
-#include "wasm-io.h"
 
 namespace wasm {
 
diff --git a/src/wasm/wat-lexer.cpp b/src/wasm/wat-lexer.cpp
index 0d1dc2794..c7959295c 100644
--- a/src/wasm/wat-lexer.cpp
+++ b/src/wasm/wat-lexer.cpp
@@ -942,7 +942,7 @@ void Lexer::lexToken() {
   curr = {tok};
 }
 
-TextPos Lexer::position(const char* c) {
+TextPos Lexer::position(const char* c) const {
   assert(size_t(c - buffer.data()) < buffer.size());
   TextPos pos{1, 0};
   for (const char* p = buffer.data(); p != c; ++p) {
diff --git a/src/wasm/wat-parser.cpp b/src/wasm/wat-parser.cpp
index aafb66019..caeccfd76 100644
--- a/src/wasm/wat-parser.cpp
+++ b/src/wasm/wat-parser.cpp
@@ -32,11 +32,11 @@
 // definitions. This phase establishes the indices and names of each module
 // element so that subsequent phases can look them up.
 //
-// The second phase, not yet implemented, parses type definitions to construct
-// the types used in the module. This has to be its own phase because we have no
-// way to refer to a type before it has been built along with all the other
-// types, unlike for other module elements that can be referred to by name
-// before their definitions have been parsed.
+// The second phase parses type definitions to construct the types used in the
+// module. This has to be its own phase because we have no way to refer to a
+// type before it has been built along with all the other types, unlike for
+// other module elements that can be referred to by name before their
+// definitions have been parsed.
 //
 // The third phase, not yet implemented, further parses and constructs types
 // implicitly defined by type uses in functions, blocks, and call_indirect
@@ -89,7 +89,7 @@ struct ParseInput {
     lexer.setIndex(index);
   }
 
-  bool empty() { return lexer == lexer.end(); }
+  bool empty() { return lexer.empty(); }
 
   std::optional<Token> peek() {
     if (!empty()) {
diff --git a/src/wat-lexer.h b/src/wat-lexer.h
index 30aa1e036..b41cbd8c1 100644
--- a/src/wat-lexer.h
+++ b/src/wat-lexer.h
@@ -166,7 +166,7 @@ public:
 
   Lexer(std::string_view buffer) : buffer(buffer) { setIndex(0); }
 
-  size_t getIndex() { return index; }
+  size_t getIndex() const { return index; }
 
   void setIndex(size_t i) {
     index = i;
@@ -206,12 +206,16 @@ public:
 
   Lexer begin() { return *this; }
 
-  Lexer end() { return Lexer(); }
+  Lexer end() const { return Lexer(); }
 
-  TextPos position(const char* c);
-  TextPos position(size_t i) { return position(buffer.data() + i); }
-  TextPos position(std::string_view span) { return position(span.data()); }
-  TextPos position(Token tok) { return position(tok.span); }
+  bool empty() const { return *this == end(); }
+
+  TextPos position(const char* c) const;
+  TextPos position(size_t i) const { return position(buffer.data() + i); }
+  TextPos position(std::string_view span) const {
+    return position(span.data());
+  }
+  TextPos position(Token tok) const { return position(tok.span); }
 
 private:
   void skipSpace();
diff --git a/src/wat-parser.h b/src/wat-parser.h
index 4bb9b62c8..7f92de9e4 100644
--- a/src/wat-parser.h
+++ b/src/wat-parser.h
@@ -17,7 +17,6 @@
 #ifndef wasm_wat_parser_h
 #define wasm_wat_parser_h
 
-#include <optional>
 #include <string_view>
 
 #include "wasm.h"
@@ -37,7 +36,7 @@ template<typename T = Ok> struct Result {
 
   Result(Result<T>& other) = default;
   Result(const Err& e) : val(std::in_place_type<Err>, e) {}
-  Result(Err&& e) : val(std::in_place_type<Err>, e) {}
+  Result(Err&& e) : val(std::in_place_type<Err>, std::move(e)) {}
   template<typename U = T>
   Result(U&& u) : val(std::in_place_type<T>, std::forward<U>(u)) {}