stage2: concat/mult of slices yields ptr to array

Author: topolarity

src/Sema.zig

@@ -8642,7 +8642,7 @@ fn zirArrayCat(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
             });
             const val = try Value.Tag.aggregate.create(anon_decl.arena(), buf);
             const decl = try anon_decl.finish(ty, val, 0);
-            if (lhs_single_ptr or rhs_single_ptr) {
+            if (lhs_ty.zigTypeTag() == .Pointer or rhs_ty.zigTypeTag() == .Pointer) {
                 return sema.analyzeDeclRef(decl);
             } else {
                 return sema.analyzeDeclVal(block, .unneeded, decl);
@@ -8817,7 +8817,7 @@ fn zirArrayMul(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
             break :blk try Value.Tag.aggregate.create(anon_decl.arena(), buf);
         };
         const decl = try anon_decl.finish(final_ty, val, 0);
-        if (is_single_ptr) {
+        if (lhs_ty.zigTypeTag() == .Pointer) {
             return sema.analyzeDeclRef(decl);
         } else {
             return sema.analyzeDeclVal(block, .unneeded, decl);

test/behavior/slice.zig

@@ -583,14 +583,27 @@ test "type coercion of pointer to anon struct literal to pointer to slice" {
     comptime try S.doTheTest();
 }
 
-test "array concat of slices gives slice" {
-    if (builtin.zig_backend != .stage1) return error.SkipZigTest; // TODO
-
+test "array concat of slices gives ptr to array" {
     comptime {
         var a: []const u8 = "aoeu";
         var b: []const u8 = "asdf";
         const c = a ++ b;
         try expect(std.mem.eql(u8, c, "aoeuasdf"));
+        if (builtin.zig_backend != .stage1) {
+            // spec change: array concat now returns pointer-to-array for slices
+            try expect(@TypeOf(c) == *const [8]u8);
+        }
+    }
+}
+
+test "array mult of slice gives ptr to array" {
+    if (builtin.zig_backend == .stage1) return error.SkipZigTest; // Stage 1 does not support multiplying slices
+
+    comptime {
+        var a: []const u8 = "aoeu";
+        const c = a ** 2;
+        try expect(std.mem.eql(u8, c, "aoeuaoeu"));
+        try expect(@TypeOf(c) == *const [8]u8);
     }
 }