Merge pull request #9611 from roc-lang/jared/range-syntax

Range syntax: `..<` (exclusive) and `..=` (inclusive)

Author: lukewilliamboswell

.gitignore

@@ -140,6 +140,7 @@ src/snapshots/**/*.html
 
 # Local claude-code settings
 .claude/
+.claude
 
 *.bak
 kcov-output/

src/backend/dev/LirCodeGen.zig

@@ -3719,14 +3719,20 @@ pub fn LirCodeGen(comptime target: RocTarget) type {
                     };
                 },
 
+                // Resolved before backend codegen: builtin `from_numeral` is
+                // folded to a constant during Monotype lowering, so the op must
+                // never reach a backend. Reaching here is an invariant failure,
+                // not a missing feature.
+                .num_from_numeral => {
+                    std.debug.panic("num_from_numeral reached the dev backend; it must be folded to a constant during Monotype lowering", .{});
+                },
                 // Unimplemented ops
                 .num_pow,
                 .num_sqrt,
                 .num_log,
                 .num_round,
                 .num_floor,
                 .num_ceiling,
-                .num_from_numeral,
                 .compare,
                 => {
                     std.debug.panic("UNIMPLEMENTED low-level op: {s}", .{@tagName(ll.op)});

src/backend/wasm/WasmCodeGen.zig

@@ -10384,7 +10384,7 @@ fn generateLowLevel(self: *Self, ll: anytype) Allocator.Error!void {
                 .{@tagName(self.procLocalLayoutIdx(args[0]))},
             ),
         },
-        .num_from_numeral => unreachable, // Resolved before backend codegen
+        .num_from_numeral => unreachable, // Folded to a constant during Monotype lowering
 
         // Box operations
         .box_box => {

src/base/mod.zig

@@ -82,6 +82,9 @@ pub const CalledVia = enum {
     /// Try.parallel(get("a"), get("b"), (|foo, bar | { foo, bar }))
     /// ```
     record_builder,
+    /// This call is the result of desugaring range syntax,
+    /// e.g. `1..<5` becomes `Iter.exclusive_range(1, 5)`.
+    range,
 };
 
 /// Represents a value written as-is in a Roc source file.