Kill non-deterministic foldUFM in TrieMap and TcAppMap

Summary:
foldUFM introduces unnecessary non-determinism that actually
leads to different generated code as explained in
Note [TrieMap determinism].

As we're switching from UniqFM to UniqDFM here you might be
concerned about performance. There's nothing that ./validate
detects. nofib reports no change in Compile Allocations, but
Compile Time got better on some tests and worse on some,
yielding this summary:

        -1 s.d.                -----            -3.8%
        +1 s.d.                -----            +5.4%
        Average                -----            +0.7%

This is not a fair comparison as the order of Uniques
changes what GHC is actually doing. One benefit from making
this deterministic is also that it will make the
performance results more stable.

Full nofib results: P108

Test Plan: ./validate, nofib

Reviewers: goldfire, simonpj, simonmar, austin, bgamari

Reviewed By: simonpj

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2169

GHC Trac Issues: #4012

1 files changed, 8 insertions, 8 deletions

diff --git a/testsuite/tests/ghc-api/apirecomp001/apirecomp001.stderr b/testsuite/tests/ghc-api/apirecomp001/apirecomp001.stderr
index 80b94dca4b..52385104cf 100644
--- a/testsuite/tests/ghc-api/apirecomp001/apirecomp001.stderr
+++ b/testsuite/tests/ghc-api/apirecomp001/apirecomp001.stderr
@@ -3,14 +3,14 @@ B.hs:4:1: warning: [-Wmissing-signatures]
     Top-level binding with no type signature:
       answer_to_live_the_universe_and_everything :: Int
 
-B.hs:5:12: warning: [-Wtype-defaults]
+B.hs:5:13: warning: [-Wtype-defaults]
     • Defaulting the following constraints to type ‘Integer’
+        (Num a0) arising from the literal ‘1’ at B.hs:5:13
         (Enum a0)
           arising from the arithmetic sequence ‘1 .. 23 * 2’ at B.hs:5:12-20
-        (Num a0) arising from the literal ‘1’ at B.hs:5:13
-    • In the first argument of ‘length’, namely ‘[1 .. 23 * 2]’
+    • In the expression: 1
+      In the first argument of ‘length’, namely ‘[1 .. 23 * 2]’
       In the first argument of ‘(-)’, namely ‘length [1 .. 23 * 2]’
-      In the expression: length [1 .. 23 * 2] - 4
 
 A.hs:7:1: warning: [-Wmissing-signatures]
     Top-level binding with no type signature: main :: IO ()
@@ -19,14 +19,14 @@ B.hs:4:1: warning: [-Wmissing-signatures]
     Top-level binding with no type signature:
       answer_to_live_the_universe_and_everything :: Int
 
-B.hs:5:12: warning: [-Wtype-defaults]
+B.hs:5:13: warning: [-Wtype-defaults]
     • Defaulting the following constraints to type ‘Integer’
+        (Num a0) arising from the literal ‘1’ at B.hs:5:13
         (Enum a0)
           arising from the arithmetic sequence ‘1 .. 23 * 2’ at B.hs:5:12-20
-        (Num a0) arising from the literal ‘1’ at B.hs:5:13
-    • In the first argument of ‘length’, namely ‘[1 .. 23 * 2]’
+    • In the expression: 1
+      In the first argument of ‘length’, namely ‘[1 .. 23 * 2]’
       In the first argument of ‘(-)’, namely ‘length [1 .. 23 * 2]’
-      In the expression: length [1 .. 23 * 2] - 4
 
 A.hs:7:1: warning: [-Wmissing-signatures]
     Top-level binding with no type signature: main :: IO ()