7f3bd69bd9
Any assignment / compound-assignment whose target chain is ROOTED at a
constant — a const-flagged global (array consts, #run consts) or a
module value const (struct consts incl.) — diagnoses 'cannot assign
through constant X' at compile time. A struct const's field write used
to compile and bus-error at runtime (issue 0116); scalars misfired
silently. A deref along the chain (p.*) breaks the root — pointer
writes stay the documented escape until the const-ness steps; a local
shadowing the const name stays writable.
Also: typed struct constants ('W : Color : Color.{...}') register —
the shape list skipped struct_literal, leaving the typed form
unresolved while the untyped one worked.
Examples: 1162 (all rejection shapes incl. the 0116 crash repro),
0178 (typed struct const reads + copy independence).
20 lines
592 B
Plaintext
20 lines
592 B
Plaintext
// Writes through a module constant are compile errors — for every target
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// chain rooted at a const: a struct const's field (this used to compile
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// and BUS-ERROR at runtime — issue 0116), an array const's element,
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// a compound assignment, and a bare scalar const. A local that shadows
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// the const name stays writable (see 0177/0178 for the value semantics).
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#import "modules/std.sx";
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Color :: struct { r, g, b: s64; }
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WHITE :: Color.{ r = 255, g = 255, b = 255 };
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K : [4]s64 : .[11, 22, 33, 44];
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N : s64 : 4;
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main :: () {
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WHITE.r = 0;
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K[0] = 5;
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K[1] += 2;
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N = 9;
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}
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