From ed44618deb7173ecfe41420fc90871b83a0d08ca Mon Sep 17 00:00:00 2001
From: Jason Beetham <beefers331@gmail.com>
Date: Tue, 27 Jul 2021 01:36:59 -0600
Subject: [PATCH] Fixed const tuples in inferred generics (#18598)

---
 compiler/semgnrc.nim                     | 33 ++++++++++++------------
 tests/tuples/tinferred_generic_const.nim | 14 ++++++++++
 2 files changed, 30 insertions(+), 17 deletions(-)
 create mode 100644 tests/tuples/tinferred_generic_const.nim

diff --git a/compiler/semgnrc.nim b/compiler/semgnrc.nim
index 4f3c50dae6..3df1e0c3f7 100644
--- a/compiler/semgnrc.nim
+++ b/compiler/semgnrc.nim
@@ -391,16 +391,24 @@ proc semGenericStmt(c: PContext, n: PNode,
       a[^1] = semGenericStmtScope(c, a[^1], flags, ctx)
       closeScope(c)
 
-  of nkVarSection, nkLetSection:
+  of nkVarSection, nkLetSection, nkConstSection:
+    let varKind =
+      case n.kind
+      of nkVarSection: skVar
+      of nkLetSection: skLet
+      else: skConst
     for i in 0..<n.len:
       var a = n[i]
-      if a.kind == nkCommentStmt: continue
-      if (a.kind != nkIdentDefs) and (a.kind != nkVarTuple): illFormedAst(a, c.config)
-      checkMinSonsLen(a, 3, c.config)
-      a[^2] = semGenericStmt(c, a[^2], flags+{withinTypeDesc}, ctx)
-      a[^1] = semGenericStmt(c, a[^1], flags, ctx)
-      for j in 0..<a.len-2:
-        addTempDecl(c, getIdentNode(c, a[j]), skVar)
+      case a.kind:
+      of nkCommentStmt: continue
+      of nkIdentDefs, nkVarTuple, nkConstDef:
+        checkMinSonsLen(a, 3, c.config)
+        a[^2] = semGenericStmt(c, a[^2], flags+{withinTypeDesc}, ctx)
+        a[^1] = semGenericStmt(c, a[^1], flags, ctx)
+        for j in 0..<a.len-2:
+          addTempDecl(c, getIdentNode(c, a[j]), varKind)
+      else: 
+        illFormedAst(a, c.config)
   of nkGenericParams:
     for i in 0..<n.len:
       var a = n[i]
@@ -410,15 +418,6 @@ proc semGenericStmt(c: PContext, n: PNode,
       # do not perform symbol lookup for default expressions
       for j in 0..<a.len-2:
         addTempDecl(c, getIdentNode(c, a[j]), skType)
-  of nkConstSection:
-    for i in 0..<n.len:
-      var a = n[i]
-      if a.kind == nkCommentStmt: continue
-      if (a.kind != nkConstDef): illFormedAst(a, c.config)
-      checkSonsLen(a, 3, c.config)
-      addTempDecl(c, getIdentNode(c, a[0]), skConst)
-      a[1] = semGenericStmt(c, a[1], flags+{withinTypeDesc}, ctx)
-      a[2] = semGenericStmt(c, a[2], flags, ctx)
   of nkTypeSection:
     for i in 0..<n.len:
       var a = n[i]
diff --git a/tests/tuples/tinferred_generic_const.nim b/tests/tuples/tinferred_generic_const.nim
new file mode 100644
index 0000000000..5ab730c38e
--- /dev/null
+++ b/tests/tuples/tinferred_generic_const.nim
@@ -0,0 +1,14 @@
+discard """
+  action: run
+"""
+block:
+  proc something(a: string or int or float) =
+    const (c, d) = (default a.type, default a.type)
+
+block:
+  proc something(a: string or int) =
+    const c = default a.type
+
+block:
+  proc something(a: string or int) =
+    const (c, d, e) = (default a.type, default a.type, default a.type)