From de41649b0e044729583e8c5061593bc7ebff594d Mon Sep 17 00:00:00 2001
From: Matthew Baulch <baulch.matt@gmail.com>
Date: Thu, 14 Jul 2016 20:51:40 +1000
Subject: [PATCH 1/3] Use target field types in tuple conversions.

---
 compiler/semexprs.nim          |  4 ++++
 tests/tuples/tconver_tuple.nim | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+)
 create mode 100644 tests/tuples/tconver_tuple.nim

diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 17feab85d7..5a27d86218 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -198,6 +198,10 @@ proc semConv(c: PContext, n: PNode): PNode =
       # separate proc from fitNode?
       if op.kind == nkSym and op.sym.isGenericRoutine:
         result.sons[1] = fitNode(c, result.typ, result.sons[1])
+      elif op.kind == nkPar and targetType.kind == tyTuple:
+        # Set type of each field in case any have type tyEmpty (eg. `@[]`)
+        for i in 0..<op.sons.len:
+          op.sons[i][1].typ = targetType.sons[i]
     of convNotNeedeed:
       message(n.info, hintConvFromXtoItselfNotNeeded, result.typ.typeToString)
     of convNotLegal:
diff --git a/tests/tuples/tconver_tuple.nim b/tests/tuples/tconver_tuple.nim
new file mode 100644
index 0000000000..b37be968a5
--- /dev/null
+++ b/tests/tuples/tconver_tuple.nim
@@ -0,0 +1,19 @@
+# Bug 4479
+
+type
+  MyTuple = tuple
+    num: int
+    strings: seq[string]
+    ints: seq[int]
+
+var foo = MyTuple((
+  num: 7,
+  strings: @[],
+  ints: @[],
+))
+
+var bar = (
+  num: 7,
+  strings: @[],
+  ints: @[],
+).MyTuple

From 05486957d433c3082c549dc0e8c0dd8ae10805a7 Mon Sep 17 00:00:00 2001
From: Matthew Baulch <baulch.matt@gmail.com>
Date: Thu, 14 Jul 2016 21:24:39 +1000
Subject: [PATCH 2/3] Fix: Correctly (and more efficiently) handle non-tuple
 conversions.

---
 compiler/semexprs.nim | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 5a27d86218..3208403d48 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -198,8 +198,9 @@ proc semConv(c: PContext, n: PNode): PNode =
       # separate proc from fitNode?
       if op.kind == nkSym and op.sym.isGenericRoutine:
         result.sons[1] = fitNode(c, result.typ, result.sons[1])
-      elif op.kind == nkPar and targetType.kind == tyTuple:
-        # Set type of each field in case any have type tyEmpty (eg. `@[]`)
+      elif op.kind == nkPar and targetType.kind == tyTuple and
+                op.sons.len > 0 and op.sons[0].kind == nkExprColonExpr:
+        # Tuple conversion: set field types in case any are tyEmpty (eg. `@[]`)
         for i in 0..<op.sons.len:
           op.sons[i][1].typ = targetType.sons[i]
     of convNotNeedeed:

From 915185dd11b6b4cdabf20cd3e9985b8044e2d3e2 Mon Sep 17 00:00:00 2001
From: Matthew Baulch <baulch.matt@gmail.com>
Date: Fri, 15 Jul 2016 20:36:11 +1000
Subject: [PATCH 3/3] Handle tuples with unnamed fields, symbols, and more.
 Less duplication.

---
 compiler/semexprs.nim          | 7 ++-----
 tests/tuples/tconver_tuple.nim | 4 ++++
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 3208403d48..96c80c64ea 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -198,11 +198,8 @@ proc semConv(c: PContext, n: PNode): PNode =
       # separate proc from fitNode?
       if op.kind == nkSym and op.sym.isGenericRoutine:
         result.sons[1] = fitNode(c, result.typ, result.sons[1])
-      elif op.kind == nkPar and targetType.kind == tyTuple and
-                op.sons.len > 0 and op.sons[0].kind == nkExprColonExpr:
-        # Tuple conversion: set field types in case any are tyEmpty (eg. `@[]`)
-        for i in 0..<op.sons.len:
-          op.sons[i][1].typ = targetType.sons[i]
+      elif op.kind == nkPar and targetType.kind == tyTuple:
+        op = fitNode(c, targetType, op)
     of convNotNeedeed:
       message(n.info, hintConvFromXtoItselfNotNeeded, result.typ.typeToString)
     of convNotLegal:
diff --git a/tests/tuples/tconver_tuple.nim b/tests/tuples/tconver_tuple.nim
index b37be968a5..306da77fe3 100644
--- a/tests/tuples/tconver_tuple.nim
+++ b/tests/tuples/tconver_tuple.nim
@@ -17,3 +17,7 @@ var bar = (
   strings: @[],
   ints: @[],
 ).MyTuple
+
+var fooUnnamed = MyTuple((7, @[], @[]))
+var n = 7
+var fooSym = MyTuple((num: n, strings: @[], ints: @[]))