From 9a5b04a98c6de51970d8b0eea3989cf610f0cd6d Mon Sep 17 00:00:00 2001
From: Brian Huffman <huffman@galois.com>
Date: Tue, 28 Jul 2020 13:34:24 -0700
Subject: [PATCH 1/2] Place parens appropriately when pretty printing types.

Fixes #835.
---
 src/Cryptol/TypeCheck/Type.hs | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/Cryptol/TypeCheck/Type.hs b/src/Cryptol/TypeCheck/Type.hs
index 32abaa77d..a7e070afe 100644
--- a/src/Cryptol/TypeCheck/Type.hs
+++ b/src/Cryptol/TypeCheck/Type.hs
@@ -834,7 +834,16 @@ instance PP (WithNames Newtype) where
 
 
 
-
+-- | The precedence levels used by this pretty-printing instance
+-- correspond with parser non-terminals as follows:
+--
+--   * 0-1: @type@
+--
+--   * 2: @infix_type@
+--
+--   * 3: @app_type@
+--
+--   * 4: @atype@
 instance PP (WithNames Type) where
   ppPrec prec ty0@(WithNames ty nmMap) =
     case ty of
@@ -867,7 +876,7 @@ instance PP (WithNames Type) where
 
           (TCTuple _, fs)     -> parens $ fsep $ punctuate comma $ map (go 0) fs
 
-          (_, _)              -> pp tc <+> fsep (map (go 5) ts)
+          (_, _)              -> optParens (prec > 3) $ pp tc <+> fsep (map (go 4) ts)
 
       TCon (PC pc) ts ->
         case (pc,ts) of

From e48e9f8302351392d597c4956b43175c465f79e5 Mon Sep 17 00:00:00 2001
From: Brian Huffman <huffman@galois.com>
Date: Tue, 28 Jul 2020 13:50:16 -0700
Subject: [PATCH 2/2] Add regression test for issue #835.

---
 tests/issues/issue835.icry        |  2 ++
 tests/issues/issue835.icry.stdout | 10 ++++++++++
 2 files changed, 12 insertions(+)
 create mode 100644 tests/issues/issue835.icry
 create mode 100644 tests/issues/issue835.icry.stdout

diff --git a/tests/issues/issue835.icry b/tests/issues/issue835.icry
new file mode 100644
index 000000000..1e6d493c9
--- /dev/null
+++ b/tests/issues/issue835.icry
@@ -0,0 +1,2 @@
+:m Float
+:t (zero : Float 5 11) <$ zero
diff --git a/tests/issues/issue835.icry.stdout b/tests/issues/issue835.icry.stdout
new file mode 100644
index 000000000..da04b3e2e
--- /dev/null
+++ b/tests/issues/issue835.icry.stdout
@@ -0,0 +1,10 @@
+Loading module Cryptol
+Loading module Cryptol
+Loading module Float
+
+[error] at <interactive>:1:1--1:28:
+  Unsolved constraints:
+    • SignedCmp (Float 5 11)
+        arising from
+        use of expression (<$)
+        at <interactive>:1:1--1:28