From 17b4721bd261d2ce5de6ca221c303276b0c5fe55 Mon Sep 17 00:00:00 2001
From: PKEuS <philipp@pkeus.de>
Date: Mon, 9 Apr 2018 11:42:38 +0200
Subject: [PATCH] C++17: Support "if constexpr" (by simplifying it to plain
 if() statement)

This might lead to complaints about constant expressions as if() statement, but should fix syntax errors.
---
 lib/tokenize.cpp      | 2 ++
 test/testtokenize.cpp | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index faa12f994..2f481d580 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -3532,6 +3532,8 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
                 // 'for each ( )' -> 'asm ( )'
                 tok->str("asm");
                 tok->deleteNext();
+            } else if (tok->strAt(1) == "constexpr") {
+                tok->deleteNext();
             } else {
                 syntaxError(tok);
             }
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index b3935c77d..3fbe8081d 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -82,6 +82,7 @@ private:
         TEST_CASE(syntax_case_default);
 
         TEST_CASE(foreach);     // #3690
+        TEST_CASE(ifconstexpr);
 
         TEST_CASE(combineOperators);
 
@@ -905,6 +906,10 @@ private:
         ASSERT_EQUALS("void f ( ) { asm ( \"char c in MyString\" ) { Console :: Write ( c ) ; } }", tokenizeAndStringify(code));
     }
 
+    void ifconstexpr() {
+        ASSERT_EQUALS("void f ( ) { if ( FOO ) { bar ( c ) ; } }", tokenizeAndStringify("void f() { if constexpr ( FOO ) { bar(c); } }"));
+    }
+
     void combineOperators() {
         ASSERT_EQUALS("; private: ;", tokenizeAndStringify(";private:;", false));
         ASSERT_EQUALS("; protected: ;", tokenizeAndStringify(";protected:;", false));