diff options
| -rw-r--r-- | changelog.md | 2 | ||||
| -rw-r--r-- | compiler/semexprs.nim | 5 | ||||
| -rw-r--r-- | compiler/semfold.nim | 4 | ||||
| -rw-r--r-- | tests/misc/tcast.nim | 3 |
4 files changed, 12 insertions, 2 deletions
diff --git a/changelog.md b/changelog.md index 7cbd4bb66..d53f5b038 100644 --- a/changelog.md +++ b/changelog.md @@ -51,7 +51,7 @@ - The `cstring` doesn't support `[]=` operator in JS backend. - +- nil dereference is not allowed at compile time. `cast[ptr int](nil)[]` is rejected at compile time. ## Compiler changes diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim index cb119b3e8..608a82715 100644 --- a/compiler/semexprs.nim +++ b/compiler/semexprs.nim @@ -1440,6 +1440,11 @@ proc buildOverloadedSubscripts(n: PNode, ident: PIdent): PNode = proc semDeref(c: PContext, n: PNode): PNode = checkSonsLen(n, 1, c.config) n[0] = semExprWithType(c, n[0]) + let a = getConstExpr(c.module, n[0], c.idgen, c.graph) + if a != nil: + if a.kind == nkNilLit: + localError(c.config, n.info, "nil dereference is not allowed") + n[0] = a result = n var t = skipTypes(n[0].typ, {tyGenericInst, tyVar, tyLent, tyAlias, tySink, tyOwned}) case t.kind diff --git a/compiler/semfold.nim b/compiler/semfold.nim index 9b21c5fa3..b92895b19 100644 --- a/compiler/semfold.nim +++ b/compiler/semfold.nim @@ -671,6 +671,10 @@ proc getConstExpr(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode var a = getConstExpr(m, n[1], idgen, g) if a == nil: return result = foldConv(n, a, g, check=true) + of nkDerefExpr, nkHiddenDeref: + let a = getConstExpr(m, n[0], idgen, g) + if a != nil and a.kind == nkNilLit: + localError(g.config, n.info, "nil dereference is not allowed") of nkCast: var a = getConstExpr(m, n[1], idgen, g) if a == nil: return diff --git a/tests/misc/tcast.nim b/tests/misc/tcast.nim index 6c6de6f8d..454801a2d 100644 --- a/tests/misc/tcast.nim +++ b/tests/misc/tcast.nim @@ -33,7 +33,8 @@ reject: discard cast[ptr](a) # bug #15623 block: if false: - echo cast[ptr int](nil)[] + let x = cast[ptr int](nil) + echo x[] block: if false: |