Tint changes during Origin Trial

Changes for M100

The @interpolate(flat) attribute must now be specified on integral user-defined IO. tint:1224
The ignore() intrinsic has been removed. Use phoney-assignment instead: ignore(expr); -> _ = expr;.
break statements in continuing blocks are now correctly validated.

Obviously infinite loops (no condition, no break) are now a validation error.

The following features have been deprecated and will be removed in M102:

The [[block]] attribute has been deprecated. tint:1324
Attributes now use the @decoration syntax instead of the [[decoration]] syntax. tint:1382
elseif has been replaced with else if. tint:1289
The [[stride]] attribute has been deprecated. tint:1381

Vector and matrix element type can now be inferred from constructor argument types. tint:1334
Added builtins degrees() and radians() for converting between degrees and radians. tint:1329
let arrays and matrices can now be dynamically indexed. tint:1352
Storage and Uniform buffer types no longer have to be structures. tint:1372
A struct declaration does not have to be followed by a semicolon. tint:1380

Fixed an issue where for-loops that contain array or structure constructors in the loop initializer statements, condition expressions or continuing statements could fail to compile. tint:1364

Taking the address of a vector component is no longer allowed.
Module-scope declarations can no longer alias a builtin name. tint:1318
It is now an error to call a function either directly or transitively, from a loop continuing block, that uses discard. tint:1302

The isNan(), isInf(), isFinite() and isNormal() builtins has been deprecated and will be removed in M101. tint:1312

New texture gather builtins: textureGather() and textureGatherCompare(). tint:1330
Shadowing is now fully supported. tint:819
The dot() builtin now supports integer vector types.
Identifiers can now start with a single leading underscore. tint:1292
Control flow analysis has been improved, and functions no longer need to return if the statement is unreachable. tint:1302
Unreachable statements now produce a warning instead of an error, to allow WGSL code to be updated to the new analysis behavior. These warnings may become errors in the future gpuweb#2378

Fixed an issue where using a module-scoped let in a workgroup_size may result in a compilation error. tint:1320

Deprecated modf() and frexp() builtin overloads that take a pointer second parameter have been removed.
Deprecated texture builtin functions that accepted a read access controlled storage texture have been removed.
Storage textures must now only use the write access control.

any() and all() now support a bool parameter. These simply return the passed argument. tint:1253
Call statements may now include functions that return a value (ignore() is no longer needed).
The interpolate(flat) attribute can now be specified on integral user-defined IO. It will eventually become an error to define integral user-defined IO without this attribute.
Matrix construction from scalar element values is now supported.

Swizzling of vec3 types in storage and uniform buffers has been fixed for Metal 1.x. tint:1249
Calling a function that returns an unused value no longer produces an FXC compilation error. tint:1259
abs() fixed for unsigned integers on SPIR-V backend

The size of an array can now be defined using a non-overridable module-scope constant
The num_workgroups builtin is now supported.

Hex floats: now correctly errors when the magnitude is non-zero, and the exponent would cause overflow. tint:1150, tint:1166
Identifiers beginning with an underscore are now correctly rejected. tint:1179