Reinstate that all constructors are explicit by default, closes #450

Author: hsutter

regression-tests/test-results/pure2-types-basics.cpp

@@ -38,7 +38,7 @@ class myclass {
 
 
 #line 20 "pure2-types-basics.cpp2"
-    public: myclass(cpp2::in<int> x, cpp2::in<std::string> s);
+    public: explicit myclass(cpp2::in<int> x, cpp2::in<std::string> s);
 
 
 #line 27 "pure2-types-basics.cpp2"

regression-tests/test-results/version

@@ -1,5 +1,5 @@
 
-cppfront compiler v0.2.1   Build 8617:0920
+cppfront compiler v0.2.1   Build 8618:1005
 Copyright(c) Herb Sutter   All rights reserved
 
 SPDX-License-Identifier: CC-BY-NC-ND-4.0

source/build.info

@@ -1 +1 @@
-"8617:0920"
+"8618:1005"

source/common.h

@@ -507,7 +507,7 @@ auto contains(
 )
     -> bool
 {
-    return s.find(value);
+    return s.find(value) != s.npos;
 }
 
 

source/cppfront.cpp

@@ -5373,7 +5373,6 @@ class cppfront
                         break;default:
                             if (
                                 func->is_constructor()
-                                && (func->is_default_constructor() || func->parameters->ssize() == 2)
                                 && !func->is_constructor_with_that()
                                 && generating_assignment_from != &n
                                 )

source/sema.h

@@ -1067,7 +1067,7 @@ class sema
             {
                 errors.emplace_back(
                     n.position(),
-                    "an 'implicit' constructor must have exactly one additional parameter besides 'this'"
+                    "an 'implicit' constructor must have at most one additional parameter besides 'this'"
                 );
                 return false;
             }