STG lint error while compiling master

While compiling e054c5f0 with the following build.mk,

BuildFlavour = devel2
include mk/flavours/$(BuildFlavour).mk

GhcStage2HcOpts += -eventlog
GhcStage1HcOpts += -eventlog

GhcLibHcOpts += -g3 -ddump-to-file -ddump-stg -dcore-lint -dstg-lint -dcmm-lint
GhcRtsHcOpts += -g3
GhcStage2HcOpts += -g3 -ddump-to-file -ddump-stg -dcore-lint -dstg-lint -dcmm-lint

I encountered this STG lint failure while compiling PprColour,

stgEqType: unequal
  PprColour
  [Char]
ghc-stage1: panic! (the 'impossible' happened)
  (GHC version 8.3.20170815 for x86_64-unknown-linux):
	  *** Stg Lint ErrMsgs: in Stg2Stg ***
  compiler/utils/PprColour.hs:62:1: warning:
       [RHS of defaultScheme :: Scheme]
      In a RHS constructor application, con type doesn't match arg types:
      Constructor type:
          PprColour
          -> PprColour
          -> PprColour
          -> PprColour
          -> PprColour
          -> PprColour
          -> Scheme
      Arg types:
          [Char]
          PprColour
          String
          String
          String
          String
  *** Offending Program ***
...

changed weight to 7

added Tbug Trac import labels

Here is a relevant excerpt from the STG program,

  defaultScheme4_r2S1 :: String
  [GblId] =
      \u []
          src<compiler/utils/PprColour.hs:(62,1)-(70,3)>
          src<compiler/utils/PprColour.hs:12:3-67>
          src<compiler/utils/PprColour.hs:12:65-66>
          src<compiler/utils/PprColour.hs:69:34-42>
          src<compiler/utils/PprColour.hs:12:52-53>
          src<compiler/utils/PprColour.hs:69:16-22>
          mappend $fMonoid[] colBold colBlueFg;
  
  defaultScheme :: Scheme
  [GblId, Unf=OtherCon []] =
      NO_CCS Scheme! [$cmempty_r2Rw
                      colBold
                      defaultScheme1_r2RY
                      defaultScheme2_r2RZ
                      defaultScheme3_r2S0
                      defaultScheme4_r2S1];

changed title from Core lint error while compiling master to STG lint error while compiling master

changed the description

It looks like this is really just another bug in STG lint: we fail to look through newtypes despite the fact that we have thrown away casts during Core-to-STG.

mentioned in issue #14118 (closed)

changed milestone to %8.4.1

Trac metadata

Trac field	Value
Differential revisions	- → D3856

mentioned in issue #14120 (closed)

closed

f17f1063 fixes this by giving up on checking of types in STG lint.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

mentioned in issue #14787 (closed)

added Phigh label