[Git][ghc/ghc][wip/int-index/rta-docs] 16 commits: Take care when simplifying unfoldings

Tue Dec 12 09:43:47 UTC 2023

Vladislav Zavialov pushed to branch wip/int-index/rta-docs at Glasgow Haskell Compiler / GHC

Commits:
d8baa1bd by Simon Peyton Jones at 2023-12-08T15:40:37+00:00
Take care when simplifying unfoldings

This MR fixes a very subtle bug exposed by #24242.

See Note [Environment for simplLetUnfolding].

I also updated a bunch of Notes on shadowing

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03ca551d by Simon Peyton Jones at 2023-12-08T15:54:50-05:00
Comments only in FloatIn

Relevant to #3458

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50c78779 by Simon Peyton Jones at 2023-12-08T15:54:50-05:00
Comments only in SpecConstr

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9431e195 by Simon Peyton Jones at 2023-12-08T15:54:50-05:00
Add test for #22238

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d9e4c597 by Vladislav Zavialov at 2023-12-11T04:19:34-05:00
Make forall a keyword (#23719)

Before this change, GHC used to accept `forall` as a term-level
identifier:

	-- from constraints-0.13
	forall :: forall p. (forall a. Dict (p a)) -> Dict (Forall p)
	forall d = ...

Now it is a parse error.

The -Wforall-identifier warning has served its purpose and is now
a deprecated no-op.

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58d56644 by Zubin Duggal at 2023-12-11T04:20:10-05:00
driver: Ensure we actually clear the interactive context before reloading

Previously we called discardIC, but immediately after set the session
back to an old HscEnv that still contained the IC

Partially addresses #24107
Fixes #23405

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8e5745a0 by Zubin Duggal at 2023-12-11T04:20:10-05:00
driver: Ensure we force the lookup of old build artifacts before returning the build plan

This prevents us from retaining all previous build artifacts in memory until a
recompile finishes, instead only retaining the exact artifacts we need.

Fixes #24118

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105c370c by Zubin Duggal at 2023-12-11T04:20:10-05:00
testsuite: add test for #24118 and #24107

MultiLayerModulesDefsGhci was not able to catch the leak because it uses
:l which discards the previous environment.

Using :r catches both of these leaks

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e822ff88 by Zubin Duggal at 2023-12-11T04:20:10-05:00
compiler: Add some strictness annotations to ImportSpec and related constructors
This prevents us from retaining entire HscEnvs.

Force these ImportSpecs when forcing the GlobalRdrEltX

Adds an NFData instance for Bag

Fixes #24107

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522c12a4 by Zubin Duggal at 2023-12-11T04:20:10-05:00
compiler: Force IfGlobalRdrEnv in NFData instance.

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188b280d by Arnaud Spiwack at 2023-12-11T15:33:31+01:00
LinearTypes => MonoLocalBinds

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8e0446df by Arnaud Spiwack at 2023-12-11T15:44:28+01:00
Linear let and where bindings

For expediency, the initial implementation of linear types in GHC
made it so that let and where binders would always be considered
unrestricted. This was rather unpleasant, and probably a big obstacle
to adoption. At any rate, this was not how the proposal was designed.

This patch fixes this infelicity. It was surprisingly difficult to
build, which explains, in part, why it took so long to materialise.

As of this patch, let or where bindings marked with %1 will be
linear (respectively %p for an arbitrary multiplicity p). Unmarked let
will infer their multiplicity.

Here is a prototypical example of program that used to be rejected and
is accepted with this patch:

```haskell
f :: A %1 -> B
g :: B %1 -> C

h :: A %1 -> C
h x = g y
  where
    y = f x
```

Exceptions:
- Recursive let are unrestricted, as there isn't a clear semantics of
  what a linear recursive binding would be.
- Destructive lets with lazy bindings are unrestricted, as their
  desugaring isn't linear (see also #23461).
- (Strict) destructive lets with inferred polymorphic type are
  unrestricted. Because the desugaring isn't linear (See #18461
  down-thread).

Closes #18461 and #18739

Co-authored-by: @jackohughes

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effa7e2d by Matthew Craven at 2023-12-12T04:37:20-05:00
Introduce `dataToTagSmall#` primop (closes #21710)

...and use it to generate slightly better code when dataToTag#
is used at a "small data type" where there is no need to mess
with "is_too_big_tag" or potentially look at an info table.

Metric Decrease:
    T18304

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35c7aef6 by Matthew Craven at 2023-12-12T04:37:20-05:00
Fix formatting of Note [alg-alt heap check]

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7397c784 by Oleg Grenrus at 2023-12-12T04:37:56-05:00
Allow untyped brackets in typed splices and vice versa.

Resolves #24190

Apparently the check was essentially always (as far as I can trace back: d0d47ba76f8f0501cf3c4966bc83966ab38cac27),
and while it does catch some mismatches, the type-checker will catch
them too. OTOH, it prevents writing completely reasonable programs.

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1f170604 by Vladislav Zavialov at 2023-12-12T12:40:25+03:00
docs: update information on RequiredTypeArguments

Update the User's Guide and Release Notes to account for the recent
progress in the implementation of RequiredTypeArguments.

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30 changed files:

- compiler/GHC/Builtin/PrimOps.hs
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/Core.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Opt/CSE.hs
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/Opt/FloatIn.hs
- compiler/GHC/Core/Opt/Pipeline.hs
- compiler/GHC/Core/Opt/Simplify/Iteration.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Data/Bag.hs
- compiler/GHC/Driver/Flags.hs
- compiler/GHC/Driver/Make.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Hs/Binds.hs
- compiler/GHC/Hs/Instances.hs
- compiler/GHC/Hs/Utils.hs
- compiler/GHC/HsToCore/Arrows.hs
- compiler/GHC/HsToCore/Binds.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/ListComp.hs
- compiler/GHC/HsToCore/Match.hs
- compiler/GHC/HsToCore/Match.hs-boot
- compiler/GHC/HsToCore/Utils.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/PostProcess.hs
- compiler/GHC/Rename/Bind.hs
- compiler/GHC/Rename/HsType.hs
- compiler/GHC/Rename/Module.hs

The diff was not included because it is too large.

View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/3316b7be5ee0d23f3da3edc3d9f446e7be560dd5...1f17060405d8dcf03f6db1b75341b70472b42f53

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/3316b7be5ee0d23f3da3edc3d9f446e7be560dd5...1f17060405d8dcf03f6db1b75341b70472b42f53
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