Numerical generics cannot be inferred

[BlobCodes]

Bug Report

Issue

Recently I tried compiling a project I last worked on with crystal v1.6.0. It suddenly did not compile, but I reduced it to the following code which compiles in Crystal v1.6.2, but not on v1.7.2:

struct Foo(A)
end

struct Bar(A)
  def initialize(foo : Foo(A))
  end
end

Bar.new(Foo(3).new)

It shows the following error:

Error: expected argument #1 to 'Bar(A).new' to be Foo(A), not Foo(3)

Overloads are:
 - Bar(A).new(foo : Foo(A))

---

Debug Information

I tried this both on master and v1.7.2.

$ crystal -v
Crystal 1.7.2 [29f9ac503] (2023-01-23)

LLVM: 13.0.1
Default target: x86_64-unknown-linux-gnu

$ krystal -v
Crystal 1.8.0-dev [072772893] (2023-02-23)

LLVM: 14.0.5
Default target: x86_64-redhat-linux-gnu

$ crystal env
CRYSTAL_CACHE_DIR=/var/home/blobcodes/.cache/crystal
CRYSTAL_PATH=lib:/usr/share/crystal/src
CRYSTAL_VERSION=1.7.2
CRYSTAL_LIBRARY_PATH=/usr/lib64/crystal
CRYSTAL_OPTS='--mcpu native'

[BlobCodes]

Commit 33b1920 (#12784) seems to have caused this regression. It works in 6b19d66.

[straight-shoota]

Resolved by #13125
Why didn't this close automatically? 🤔