Merge branch 'Vexu-tagname'

closes #4559
closes #3991

3 files changed, 42 insertions, 1 deletions

diff --git a/test/compile_errors.zig b/test/compile_errors.zig
index 138f7a7633..0260160dca 100644
--- a/test/compile_errors.zig
+++ b/test/compile_errors.zig
@@ -3,6 +3,15 @@ const builtin = @import("builtin");
 const Target = @import("std").Target;
 
 pub fn addCases(cases: *tests.CompileErrorContext) void {
+    cases.addTest("@tagName on invalid value of non-exhaustive enum",
+        \\test "enum" {
+        \\    const E = enum(u8) {A, B, _};
+        \\    _ = @tagName(@intToEnum(E, 5));
+        \\}
+    , &[_][]const u8{
+        "tmp.zig:3:18: error: no tag by value 5",
+    });
+
     cases.addTest("@ptrToInt with pointer to zero-sized type",
         \\export fn entry() void {
         \\    var pointer: ?*u0 = null;
diff --git a/test/stage1/behavior/cast.zig b/test/stage1/behavior/cast.zig
index 76d3b784ec..d2267a3753 100644
--- a/test/stage1/behavior/cast.zig
+++ b/test/stage1/behavior/cast.zig
@@ -491,6 +491,17 @@ test "@intToEnum passed a comptime_int to an enum with one item" {
     expect(x == E.A);
 }
 
+test "@intToEnum runtime to  an extern enum with duplicate values" {
+    const E = extern enum(u8) {
+        A = 1,
+        B = 1,
+    };
+    var a: u8 = 1;
+    var x = @intToEnum(E, a);
+    expect(x == E.A);
+    expect(x == E.B);
+}
+
 test "@intCast to u0 and use the result" {
     const S = struct {
         fn doTheTest(zero: u1, one: u1, bigzero: i32) void {
diff --git a/test/stage1/behavior/enum.zig b/test/stage1/behavior/enum.zig
index 18489ba24b..b6cb86a363 100644
--- a/test/stage1/behavior/enum.zig
+++ b/test/stage1/behavior/enum.zig
@@ -198,7 +198,17 @@ test "@tagName" {
     comptime expect(mem.eql(u8, testEnumTagNameBare(BareNumber.Three), "Three"));
 }
 
-fn testEnumTagNameBare(n: BareNumber) []const u8 {
+test "@tagName extern enum with duplicates" {
+    expect(mem.eql(u8, testEnumTagNameBare(ExternDuplicates.B), "A"));
+    comptime expect(mem.eql(u8, testEnumTagNameBare(ExternDuplicates.B), "A"));
+}
+
+test "@tagName non-exhaustive enum" {
+    expect(mem.eql(u8, testEnumTagNameBare(NonExhaustive.B), "B"));
+    comptime expect(mem.eql(u8, testEnumTagNameBare(NonExhaustive.B), "B"));
+}
+
+fn testEnumTagNameBare(n: var) []const u8 {
     return @tagName(n);
 }
 
@@ -208,6 +218,17 @@ const BareNumber = enum {
     Three,
 };
 
+const ExternDuplicates = extern enum(u8) {
+    A = 1,
+    B = 1,
+};
+
+const NonExhaustive = enum(u8) {
+    A,
+    B,
+    _,
+};
+
 test "enum alignment" {
     comptime {
         expect(@alignOf(AlignTestEnum) >= @alignOf([9]u8));