Merge remote-tracking branch 'origin/master' into llvm8

test/compile_errors.zig

@@ -1,6 +1,15 @@
 const tests = @import("tests.zig");
 
 pub fn addCases(cases: *tests.CompileErrorContext) void {
+    cases.addTest(
+        "@truncate undefined value",
+        \\export fn entry() void {
+        \\    var z = @truncate(u8, u16(undefined));
+        \\}
+    ,
+        ".tmp_source.zig:2:30: error: use of undefined value",
+    );
+
     cases.addTest(
         "return invalid type from test",
         \\test "example" { return 1; }
@@ -3335,7 +3344,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
     cases.add(
         "truncate sign mismatch",
         \\fn f() i8 {
-        \\    const x: u32 = 10;
+        \\    var x: u32 = 10;
         \\    return @truncate(i8, x);
         \\}
         \\

test/stage1/behavior/error.zig

@@ -330,3 +330,8 @@ test "optional error set is the same size as error set" {
     expect(S.returnsOptErrSet() == null);
     comptime expect(S.returnsOptErrSet() == null);
 }
+
+test "debug info for optional error set" {
+    const SomeError = error{Hello};
+    var a_local_variable: ?SomeError = null;
+}

test/stage1/behavior/truncate.zig

@@ -6,3 +6,26 @@ test "truncate u0 to larger integer allowed and has comptime known result" {
     const y = @truncate(u8, x);
     comptime expect(y == 0);
 }
+
+test "truncate.u0.literal" {
+    var z = @truncate(u0, 0);
+    expect(z == 0);
+}
+
+test "truncate.u0.const" {
+    const c0: usize = 0;
+    var z = @truncate(u0, c0);
+    expect(z == 0);
+}
+
+test "truncate.u0.var" {
+    var d: u8 = 2;
+    var z = @truncate(u0, d);
+    expect(z == 0);
+}
+
+test "truncate sign mismatch but comptime known so it works anyway" {
+    const x: u32 = 10;
+    var result = @truncate(i8, x);
+    expect(result == 10);
+}