From 3d6cbcf8a60eba97f6f2ddd4205a964ad4d458f7 Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@red-bean.com>
Date: Sun, 14 Nov 2021 12:20:27 -0800
Subject: [PATCH] Remove IndexableLength::Specializable variant.

Specializable constants are no longer permitted as array lengths, so this case
should not arise in valid code.
---
 src/back/spv/index.rs |  4 ----
 src/proc/index.rs     | 10 +++++-----
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/back/spv/index.rs b/src/back/spv/index.rs
index 0fc4c3ffe3..30ac58472f 100644
--- a/src/back/spv/index.rs
+++ b/src/back/spv/index.rs
@@ -109,10 +109,6 @@ impl<'w> BlockContext<'w> {
                 let length_id = self.write_runtime_array_length(sequence, block)?;
                 Ok(MaybeKnown::Computed(length_id))
             }
-            crate::proc::IndexableLength::Specializable(constant) => {
-                let length_id = self.writer.constant_ids[constant.index()];
-                Ok(MaybeKnown::Computed(length_id))
-            }
         }
     }
 
diff --git a/src/proc/index.rs b/src/proc/index.rs
index 69dd6c2bba..b6dd1e4b56 100644
--- a/src/proc/index.rs
+++ b/src/proc/index.rs
@@ -49,10 +49,6 @@ pub enum IndexableLength {
     /// Values of this type always have the given number of elements.
     Known(u32),
 
-    /// The value of the given specializable constant is the number of elements.
-    /// (Non-specializable constants are reported as `Known`.)
-    Specializable(crate::Handle<crate::Constant>),
-
     /// The number of elements is determined at runtime.
     Dynamic,
 }
@@ -65,7 +61,11 @@ impl crate::ArraySize {
                 K {
                     specialization: Some(_),
                     ..
-                } => IndexableLength::Specializable(k),
+                } => {
+                    // Specializable constants are not supported as array lengths.
+                    // See valid::TypeError::UnsupportedSpecializedArrayLength.
+                    return Err(ProcError::InvalidArraySizeConstant(k));
+                }
                 ref unspecialized => {
                     let length = unspecialized
                         .to_array_length()