Assigning a boolean literal to a bool-typed class field causes a compiler crash

[alangpierce]

Here's a simple test case that crashes when I run it through asc:

class A {
  boolValue: bool;
}

export function test(): void {
  let a: A;
  a.boolValue = true;
}

I get this error:

$ asc src/index.ts -b test.wasm

/Users/alanpierce/code/assemblyscript/node_modules/binaryen/index.js:6
if(m){var da,ea;a.read=function(b,d){var c=p(b);c||(da||(da=require("fs")),ea||(ea=require("path")),b=ea.normalize(b),c=da.readFileSync(b));return d?c:c.toString()};a.readBinary=function(b){b=a.read(b,!0);b.buffer||(b=new Uint8Array(b));assert(b.buffer);return b};1<process.argv.length&&(a.thisProgram=process.argv[1].replace(/\\/g,"/"));a.arguments=process.argv.slice(2);process.on("uncaughtException",function(b){if(!(b instanceof fa))throw b;});process.on("unhandledRejection",function(){process.exit(1)});
                                                                                                                                                                                                                                                                                                                                                                                                                                                     ^
abort(). Build with -s ASSERTIONS=1 for more info.

I'll see if I can contribute a fix for this. Any pointers would be helpful.

[MaxGraey]

All class instances should be allocated. Try this:

import 'allocator/tlsf';

class A {
  boolValue: bool;
}

export function test(): void {
  let a = new A();
  a.boolValue = true;
}

[alangpierce]

@MaxGraey That gives the same compiler error, I just left out the allocator bit to make the test case a little smaller. Failing to allocate would just result in a runtime crash (or maybe undefined behavior), right? Agreed that your modified code is certainly more realistic.

[dcodeIO]

I think this is due to emitting a store using a wrong byte size, something like type.size >> 3 which isn't correct for bools with size=1 (should use type.byteSize instead). Is this still present in master?

[alangpierce]

@dcodeIO Yes, I'm on master.

[MaxGraey]

@dcodeIO I approved this cause to error, hmm

[alangpierce]

@dcodeIO thanks, the type.size >> 3 thing was exactly the issue. I just put up a PR to fix.

[dcodeIO]

Thanks, looks good. Wdyt of checking the load (when getting a property) in the test case as well, just to be sure?