fix(cpp1): support assignment from expression list

regression-tests/pure2-bugfix-for-assign-expression-list.cpp2

@@ -0,0 +1,10 @@
+main: () = {
+  vec: type == std::vector<int>;
+  v: vec              = (0);
+  v                   = ();
+  [[assert: v == :vec = ()]]
+  v                   = (1);
+  [[assert: v == :vec = (1)]]
+  v                   = (2, 3);
+  [[assert: v == :vec = (2, 3)]]
+}

regression-tests/test-results/pure2-bugfix-for-assign-expression-list.cpp

@@ -0,0 +1,30 @@
+
+#define CPP2_USE_MODULES         Yes
+
+//=== Cpp2 type declarations ====================================================
+
+
+#include "cpp2util.h"
+
+
+
+//=== Cpp2 type definitions and function declarations ===========================
+
+#line 1 "pure2-bugfix-for-assign-expression-list.cpp2"
+auto main() -> int;
+
+
+//=== Cpp2 function definitions =================================================
+
+#line 1 "pure2-bugfix-for-assign-expression-list.cpp2"
+auto main() -> int{
+  using vec = std::vector<int>;
+  vec v {0}; 
+  v                   = {  };
+  cpp2::Default.expects(v==vec{}, "");
+  v                   = { 1 };
+  cpp2::Default.expects(v==vec{1}, "");
+  v                   = { 2, 3 };
+  cpp2::Default.expects(std::move(v)==vec{2, 3}, "");
+}
+

regression-tests/test-results/pure2-bugfix-for-assign-expression-list.cpp2.output

@@ -0,0 +1,2 @@
+pure2-bugfix-for-assign-expression-list.cpp2... ok (all Cpp2, passes safety checks)
+

regression-tests/test-results/pure2-types-smf-and-that-1-provide-everything.cpp

@@ -143,7 +143,7 @@ auto main() -> int{
     CPP2_UFCS(print, z, "   cp-assign     ", " <- ");
     CPP2_UFCS(print, y, "", "\n");
 
-    z = std::move(y);
+    z = { std::move(y) };
     CPP2_UFCS(print, std::move(z), "   mv-assign     ", " <- ");
     CPP2_UFCS(print, std::move(y), "", "\n");
 }

regression-tests/test-results/pure2-types-smf-and-that-2-provide-mvconstruct-and-cpassign.cpp

@@ -148,7 +148,7 @@ auto main() -> int{
     CPP2_UFCS(print, z, "   cp-assign     ", " <- ");
     CPP2_UFCS(print, y, "", "\n");
 
-    z = std::move(y);
+    z = { std::move(y) };
     CPP2_UFCS(print, std::move(z), "   mv-assign     ", " <- ");
     CPP2_UFCS(print, std::move(y), "", "\n");
 }

regression-tests/test-results/pure2-types-smf-and-that-3-provide-mvconstruct-and-mvassign.cpp

@@ -147,7 +147,7 @@ auto main() -> int{
     CPP2_UFCS(print, z, "   cp-assign     ", " <- ");
     CPP2_UFCS(print, y, "", "\n");
 
-    z = std::move(y);
+    z = { std::move(y) };
     CPP2_UFCS(print, std::move(z), "   mv-assign     ", " <- ");
     CPP2_UFCS(print, std::move(y), "", "\n");
 }

regression-tests/test-results/pure2-types-smf-and-that-4-provide-cpassign-and-mvassign.cpp

@@ -147,7 +147,7 @@ auto main() -> int{
     CPP2_UFCS(print, z, "   cp-assign     ", " <- ");
     CPP2_UFCS(print, y, "", "\n");
 
-    z = std::move(y);
+    z = { std::move(y) };
     CPP2_UFCS(print, std::move(z), "   mv-assign     ", " <- ");
     CPP2_UFCS(print, std::move(y), "", "\n");
 }

regression-tests/test-results/pure2-types-smf-and-that-5-provide-nothing-but-general-case.cpp

@@ -153,7 +153,7 @@ auto main() -> int{
     CPP2_UFCS(print, z, "   cp-assign     ", " <- ");
     CPP2_UFCS(print, y, "", "\n");
 
-    z = std::move(y);
+    z = { std::move(y) };
     CPP2_UFCS(print, std::move(z), "   mv-assign     ", " <- ");
     CPP2_UFCS(print, std::move(y), "", "\n");
 }

source/cppfront.cpp

@@ -3525,7 +3525,23 @@ class cppfront
                     emit(*x.op);
                 }
                 printer.print_cpp2(" ", n.position());
-                emit(*x.expr);
+
+                //  When assigning a single expression-list, we can
+                //  take over direct control of emitting it without needing to
+                //  go through the whole grammar, and surround it with braces
+                if (
+                    x.op->type() == lexeme::Assignment
+                    && x.expr->is_expression_list()
+                    )
+                {
+                    printer.print_cpp2( "{ ", n.position() );
+                    emit(*x.expr->get_expression_list(), false);
+                    printer.print_cpp2( " }", n.position() );
+                }
+                //  Otherwise, just emit the general expression as usual
+                else {
+                    emit(*x.expr);
+                }
             }
         }
     }