certain un-annotated declarations or incorrect let annotation → compiler thread blocked indefinitely in an MVar operation

[lue-bird]

(There are probably actually different underlying type inference problems involving let and recursion with a similar outcome, but multiple individual cases are often crammed into one issue, so distinction is hard)

• incorrect record field setting with let Compiler crash (thread blocked indefinitely in an MVar operation) instead of type error elm/compiler#2206
• correct record field setting with let Compiler crash (index out of bounds) elm/compiler#1890
• record destructuring with let Compiler gives an error on destructuring a non existent record field elm/compiler#1748
• (very simple example) with let Rigid variables in internal annotations need top-level annotation elm/compiler#1839
• (very simple example) with let Compiler crash on generic comparable tuples in let-bindings elm/compiler#1793
• (very simple example) with let Compiler panic when unifying inner skolem with an outer unification variable elm/compiler#2301
• argument type incorrect with let Compiler bug [rank = 1] elm/compiler#2013
• argument type incorrect with let Incorrect type signature causing [rank = 1] error elm/compiler#1974
• (simple example) argument type incorrectly different full type with let "index out of bounds" based on alphabetical order in let expression elm/compiler#1975
• (simple examples) argument type incorrectly different type variable with let Compiler bug [ rank = 2 ] and [ rank = 3 ] elm/compiler#2014
• (non-minimal example) incorrectly typed tuple with let Compiler Bug: Pathological example elm/compiler#2338
• (simple example) types correct, parametric types with let Rank compiler bug with parametric types elm/compiler#2001
• (simple example) let result type incorrect Thread blocked indefinitely in an MVar operation with incorrect function signature within let elm/compiler#2100
• (simple example) correct type with let and phantom types Error called at Type/Solve.hs:206:15 -- thread blocked indefinitely in an MVar operation -- caused by type signature with type variable with wrapped phantom types elm/compiler#2185
• (simple example) let declaration recursion directly into themselves with too many and too widely typed arguments https://github.com/elm/compiler
  /issues/2184
• (simple example) un-annotated let in un-annotated declaration Type annotation crashes the compiler elm/compiler#2296
• (long example) with let thread blocked indefinitely in an MVar operation elm/compiler#2146
• (long example) with let and records Compiler error: index out of bound (3,3) somewhere in Data/Vector/Generic/Mutable.hs elm/compiler#2148
• multiple examples elm-19: thread blocked indefinitely in an MVar operation elm/compiler#1789
• (short example) mutual recursion with correct type Map.! when exposing mutually recursive function without type annotations elm/compiler#2119
• (simple example) recursion with incorrect type Compiler bug: "? [rank = 1]" in Type/Solve.hs elm/compiler#2153
• (no simple example) Elm 0.19.1 compiler reports a bug in itself elm/compiler#2035