[project @ 2003-02-19 15:54:05 by simonpj]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcRnTypes.lhs

diff --git a/ghc/compiler/typecheck/TcRnTypes.lhs b/ghc/compiler/typecheck/TcRnTypes.lhs
index 790911b..1e58edd 100644 (file)
--- a/ghc/compiler/typecheck/TcRnTypes.lhs
+++ b/ghc/compiler/typecheck/TcRnTypes.lhs
@@ -283,6 +283,11 @@ data TcGblEnv
                -- and then in the mutable EPS, because the InstEnv for this module
                -- is constructed (in principle at least) only from the modules
                -- 'below' this one, so it's this-module-specific
+               --
+               -- On the other hand, a declaration quote [d| ... |] may introduce
+               -- some new instance declarations that we *don't* want to persist
+               -- outside the quote, so we tiresomely need to revert the InstEnv
+               -- after finishing the quote (see TcSplice.tcBracket)
 
                -- Now a bunch of things about this module that are simply 
                -- accumulated, but never consulted until the end.